Nano-engineering coatings and thin films

Resume : Thin films are today considered as full part functional nanomaterials. During the last decades, applications of quasi two-dimensional nano-engineered coatings and multi-phase / multi-layered thin films have been widely extended in the fields of nanomechanics, biology, tribology or optics. These developments were possible owing to improvements in tailoring innovative approaches. Accordingly, the level of complexity of structures and nanostructures has increased to a point where imaging, metrology and chemical analysis are compulsory for any better understanding, thus optimizing of these fascinating nanomaterials. In this context, advanced electron microscopy provides powerful tools to investigate such features at the desired scale. Focused Ion Beam (FIB) prep techniques help now to take away very well adapted samples for optimized Transmission Electron Microscopy (TEM) studies. Aberration-corrected instruments allow to access almost any desired level of resolution from a spatial and chemical point of view, even in 3D. In situ techniques, either nanomechanical, electrical or environmental solicitation can be used for a better characterization under conditions close to the future using conditions. The purpose of this contribution is to illustrate such approaches, mostly in the case of thin films problematics. Acknowledgements Thanks are due to CLYM (www.clym.fr) for access to microscopes in Lyon. This work is partly supported by the French ANR project ‘3DCLEAN’ ANR-15-CE09-0009.

Resume : Micro and nano-patterning of surfaces is a still challenge in the field of MEMS and NEMS devices assembled via top-down approaches. Consequently, a possible strategy to tackle this problem consists in the development of 3D micro and nano-fabrication processes with high flexibility of use, wide versatility of materials and substrates choice and high deposition rates to process an object in a short period of time. Among the foreseen technologies, atmospheric pressure plasma treatments are relatively low-cost and can be envisaged in a wide range of applications from electronic to medicine. We propose a new process, named Discribe, based on an atmospheric pressure plasma in which a precursor is introduced by means of a nano-capillary. This novel approach allows any end-user to “write/erase” patterns over a surface without resorting to specific and expensive masks. In addition, tridimensional printing can be easily solved by using a moving XYZ stage where the gap between the capillary and the substrate surface can be adjusted on demand. Composite coatings can be deposited alike by adding nanoparticles in the precursor flow. Overall, this new process of additive manufacturing by atmospheric plasma offers an unusually high resolution at low cost. This study demonstrates the possibility to deposit sub-micrometric localized coatings − spots, lines or even more complex shapes – made of amorphous hydrogenated carbon (a-C:H) [1]. [1] Boileau et al., J. Phys. D: Appl. Phys. 49 (2016) 445306

Resume : High-entropy alloys consist of at least 5 different metals in near-equimolar concentrations. A typical example is CoCrCuFeNi. In contrast to the expectation, this material grows as a (111) out-of-plane fiber textured FCC thin film. In the present study, this material is reactively sputtered from a solid target mounted on a two inch magnetron. The influence of oxygen or nitrogen addition to the plasma is investigated. Firstly, the influence of the reactive gas on the discharge voltage, total pressure and deposition rate is studied. In this way, the metallic and the poisoned mode are characterized. Secondly, thin films with a thickness of 500 nm are deposited by adjusting the deposition time. The samples are characterized by XRD, SEM, EDX-WDX and XRR to study the influence of the reactive gas addition on the film morphology, microstructure and texture. The elastic properties are investigated with the aid of PU (Picosecond Ultrasonics) and BLS (Brillouin Light Scattering). A study of the electrical properties of the film is performed by measuring the film resistivity during air exposure by a four probe method as a function of the sample temperature. By cycling the temperature during these latter measurements, film oxidation is investigated. These samples were produced from two different experimental setups, to eliminate chamber dependencies.

Resume : Abstract : Graphene thin films on Diamond-like carbon (DLC) films have been obtained on Si or transparent substrates like quartz by pulse laser deposition (PLD) of carbon. Then a transition metal is evaporated (Fe, Co, Ni) at ambient temperature. A subsequent thermal annealing performed in Ultra High Vacuum condition up to 973 K. allows the surface formation of a thin graphitic film on top of the DLC, soon described in Appl. Phys. A, Materials Science & Processing, 71, 433–439 (2000). This film display electrical conductivity combined with high optical transmission and work function, and therefore it could be a possible candidate for transparent electrodes (high conductivity of transparency). Film properties (Thin graphitic layers as well as DLC) has been investigated as a function of many PLD parameters (PLD fluence and time, annealing temperature, nature of the catalyst). The formation of graphene films on top of DLC have been characterized by different techniques including X-ray photoemission, electron-energy-loss spectroscopies, Raman scattering, Nuclar Reaction analysis (NRA).

Resume : Using a metal-organic tungsten based precursor, a fluorine-free tungsten thin film has been obtained. The process deposition recipe includes a plasma-enhanced CVD step and ALD cycles. This tungsten thin film can be used as low resistance liner and barrier to fluorine diffusion for several applications in replacement of the classical TiN liner. A set of physicochemical characterizations including XRR, in-plane XRD, WDXRF, plasma profiling time of flight mass spectrometry (PPTOFMS) and SEM/TEM observations has been realized in order to study the W thin film structure and properties. The film is perfectly conformal whatever the structure size tested (from tens of nanometers to micrometers wide). We have also highlighted that the F-free W film exhibits the lowest electrical resistivity phase (α-W) but is not pure. Indeed, in addition to a top surface oxidation, a layer located at the W film / substrate interface is present. This interface layer contains impurities, including C and O, due to ligand decomposition. It might be deposited during the soak step or during the PECVD step. The W liner with thicknesses ranging from 3 to 4 nm has been implemented on PCRAM structures in order to evaluate its impact on contact plug resistivity. First electrical results are promising and demonstrate the interest of using a F-free low resistance W liner. At the aspect ratio studied, the gain in terms of contact plug resistivity is about 20 % compare to the process of reference using a TiN liner.

Resume : The dependence of the morphology of an amorphous silicon (a-Si) film on the deposition technique is known since the late 1970s. Chemical vapor deposition (CVD) supports a non-columnar growth of the a-Si, while physical vapor deposition (PVD) yields a columnar growth including branches. Further, more recent investigations discover an interaction of layers morphology and embedded hydrogen, mainly affecting layer characteristics as e.g. surface passivation capability. Moreover, literature reports the growth of an a-Si layer on crystalline silicon within the very moment of plasma ignition in a CVD process. Morphology depended characteristics as well as the existence of different layers can be observed by indirect characterization methods like growth rate analysis, nuclear resonant reaction analysis and/or Fourier transformed infrared spectroscopy. Until now, a cross-check of these indirect methods by direct investigation, like electron microscopy observations, was not possible, as the morphological effects are on an atomic scale. By comparing different a-Si morphologies in a multi-layer stack, direct observation of an in situ grown layer in the early beginning of a CVD a-Si deposition by tunnel electron microscopy becomes possible. The authors would like to present their latest results and insights emerged by using a sub atomic resolution transmission electron microscope located in the noise-free laboratories of the Binnig and Rohrer Nanotechnology Center at IBM Research-Zurich.

Resume : Densified and highly optically transparent zirconium dioxide films (extinction coefficient of 2 x 10-4 at 550 nm) were prepared by reactive ac magnetron sputtering on a floating substrate in argon-oxygen gas mixtures. We used two unbalanced magnetrons in a closed-field configuration equipped with zirconium targets (100 mm in diameter) driven by a mid-frequency ac power supply producing sinusoidal waveforms of the target voltage and current. The depositions of the films were performed at the repetition frequency of about 85 kHz, the total pressure close to 1 Pa and the average target power densities of 5 – 15 Wcm-2 which are used in industrial ac magnetron sputtering systems. We found that a simple feed-back pulsed reactive gas flow control [1] is very effective also in industrially-demanded reactive ac magnetron sputtering. The method led to a stable, arc-free sputtering process with enhanced deposition rates (up to 84 nm/min), being up to 2.5 times higher compared with the depositions in an oxide mode at the same target power density. We will report on deposition characteristics, mechanical and optical properties of the films and their surface morphology. [1] J. Vlček, J.Rezek, J. Houška, R. Čerstvý, R. Bugyi, Surf. Coat. Technol. 236 (2013) 550.

Resume : Mn+1AXn phases belong to a group of ternary nitrides or carbides, where M denotes an early transition metal, A denotes mostly a group III or IVA element and X is either nitrogen or carbon. In recent years, an increasing number of investigations on the synthesis and characterization on crystalline Mn+1AXn phases have been published which focus on their suitability for industrial applications, e.g. as protective coatings. Due to the mixture of strong covalent MX bonds and weak ionic MA bonds, these materials often exhibit a high corrosion resistance as well as good electrical conductivity and thermal stability. However, these properties strongly depend on the material*s crystallinity. Ti2AlN MAX-phase thin films were synthetized on various substrates in a reactive sputter mode by a multilayer-deposition of AlN and Ti single layers under variation of the double layer thickness, followed by a subsequent annealing step. The synthesis results were investigated by elemental analysis and electron microscopy. The evolving microstructure with a preferential orientation in the texture was analyzed by polarized Raman spectroscopy and XRD. Besides temperature and annealing time, the double layer thickness turned out to be a key parameter to adjust the orientation and grain size.

Resume : Partial substitution of aluminium by scandium in the wurtzite structure of aluminium nitride (AlN) leads to a large increase of the piezoelectric response by more than a factor of 2. Therefore, aluminium scandium nitride (ASN) thin films attracted much attention to improve piezoelectric MEMS devices such as RF filters, sensors, micro actuators and energy harvesting devices. In this work, process-microstructure-property relationships of ASN thin films containing up to 40% Sc were investigated. Like AlN thin films, ASN films are as well sputter deposited at 300–350 °C with pulsed DC or RF powered magnetrons. In order to achieve piezoelectric active films with a high Sc concentration, the influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response was carefully investigated. X-Ray diffraction (XRD) was used to confirm c-axis textured film growth. Such films exhibit for the (002) ASN peak a rocking curve of around 1.3–2° (FHWM). The films were further analysed by electron microscopy and the Sc content was determined by energy-dispersive X-ray spectroscopy (EDX). A good compositional homogeneity in the range of 0.5–1 at% was achieved between border and centre of 200-mm wafers. So far, we obtained ASN films with transversal and longitudinal piezoelectric coefficients up to e31,f = -2.37 C/m2 and d33,f = 10.1 pm/V, respectively. This corresponds to films with more than twice as large piezoelectric coefficients as AlN.

Resume : Reflective mirror coatings made of iridium are often used in X-ray telescopes investigating astronomical sources at photon energies below 10 keV. Due to the reduced mirror thickness (< 1 mm) for next generation X-ray observatories, enhanced coating properties are required. In particular, low coating stress is needed to avoid unwanted deformations of the initial precisely shaped mirror substrates, which would affect the angular resolution of the telescope. The development of thin iridium films deposited using an RF-magnetron sputtering technique presented here is focused on the influence of the substrate material quality and the deposition parameters on the thin film properties. XRD, XRR and AFM characterization methods have been used. Correlations between coating density, surface micro-roughness, crystalline structure of the iridium layers and the expected reflectivity as well as stress-induced deformation of the X-ray mirror will be presented and discussed.

Resume : Multilayered Cr0.50Al0.50N and Cr0.51Al0.46Y0.03N coatings were deposited on M2 and 316 steel substrates and heated to 1000 ºC in air for 2 h to study their oxidation mechanism and thermal stability. X-ray diffraction, glow-discharge optical emission spectroscopy and transmission electron microscopy coupled with spatially resolved microanalysis techniques are used to investigate the nanostructure, constituent phases and chemical elemental distribution of the as-prepared and oxidized samples. The reactive element effect of Y is confirmed but differs from the typical observed in alloys. The interdiffusion of substrate elements plays an important role in the oxidation process influencing the corrosion products. The presence of yttrium retards the iron outward diffusion by forming oxides in M2 and yttrium nitride in 316 steels. The microstructural analysis determined that yttrium migrates to the grains and interface of the oxide scale and to the nitride column boundaries.

Resume : Particulate films consisting of thermochromic vanadium dioxide (VO2) have been obtained by reactive magnetron sputtering onto In2O3:Sn coated glass substrates. These films consist of VO2 particles of adequate size to cause light scattering—and hence diffuse transmittance—in the visible region. When these films are heated up above the temperature at which the thermochromic transition takes place, the particles switch from a semiconducting to a metallic state, thereby affecting the overall scattering properties. In this work, layers consisting of particles of different shapes and sizes have been studied by scanning electron microscopy, atomic force microscopy and optical spectrophotometry. The optical properties of the films, including the spectral absorption and scattering coefficients, have been studied below and above the transition temperature. In addition, the experimental optical properties have been reconciled with a semi-quantitative model based on Lorentz-Mie theory and the Grenfell-Warren approximation.

Resume : The ability of most hard materials to deform inelastically is usually rather limited since the activation of dislocation glide on most slip systems in hard nanocrystalline ceramic materials requires much higher stress than that for brittle fracture along grain boundaries of a low cohesive energy. On the contrary, materials with enhanced plasticity are usually not very strong. An enhancement of the material fracture toughness without compromising its strength is thus rather challenging. We will demonstrate various innovative material design strategies for fracture toughness enhancement of brittle ceramic nanostructured materials, which rely on a variation in material microstructure and mechanical property depth-distributions, and dedicated grain-boundary and interface design. The film characterization in terms of stiffness, fracture stress and toughness was based mainly on in-situ micromechanical testing of microcantilever beams prepared by focused ion beam milling. Besides strategies to enhance fracture toughness by transformation toughening, coherency strain or intrinsic compressive stress, the main focus will be on microstructural design of thin films to control crack propagation. The microstructure- and property-dependent mechanisms controlling crack propagation (e.g. deflection by weak interfaces or crack path tortuosity) with subsequent toughness enhancement will be discussed in detail for various material combinations (hard/soft crystalline/amorphous and crystalline/crystalline materials). Special attention will be paid to nanocrystalline materials with sculptured chevron-like microstructure, where crack propagation is inhibited by deflection of cracks at the grain boundaries and/or interfaces between stiff and elastic constituents. In this way, even common nanocrystalline brittle materials may exhibit considerably enhanced plasticity and fracture toughness achieving values more than 150% of their monolithic counterparts with columnar microstructure.

Resume : Transparent conductive films (TCFs) is high transparency in visible light(λ=380～780nm)with nearly metallic conductivity. They are important materials and represent more than 50% in functional films. In this paper, highly conductive and transparent TCFs of carbon nanotubes were fabricated by incorporating Nafion® into carbon nanotubes (CNTs) layers. The transparency and electrical conductivity properties of the CNTs/Nafion® thin films were significantly improved by the 3,4-ethylenedioxythiophene (EDOT) incorporation. Conductive carbon nanotubes/Nafion® (CNTs/Nafion®) composites are prepared based on filtration technology. CNTs are first dispersed in ethanol mixed with different amounts of Nafion® and then driven by ultrasonic. From these mixtures CNTs/Nafion® composites were dipped in EDOT. The dispersion of CNTs/Nafion® is characterized by infrared spectroscopy, scanning electron microscopy and UV–vis spectra. When applying adequate preparation conditions, CNTs are well dispersed and homogeneously incorporated in the Nafion®. Using the developed process, CNTs/Nafion® thin films that are uniform and the dispersion of CNTs with Nafion® connected with one another to form an interweaving films and highly transparent have been fabricated. The resistivity and optical transmittance of CNTs/Nafion® with EDOT thin film were 82 KΩ/□ and over 69% with optimum condition when the volume of CNTs/Nafion® was 0.3mL and the ratio of Nafion® was 2.5%. With the optimization of the composition of Nafion® composite, CNTs/ Nafion® thin films might potentially offer better or comparable performances as the conductive oxides.

Resume : Polyimide (PI) is one of the most popular polymers due to its outstanding physicochemical properties, such as thermostability, corrosion resistant, radiation resistant, chemical stability and so on. These unique properties make PI have wide applications in electronics, automotive and aerospace industries. However, it’s hard to deposite metal film on PI film, which is unfavourable for PI film to use in flexible electronic device. Compared with other surface coating technology, ion implantation is a idea mothod for the surface modification of PI film. In this paper, different ions are used to implant into the PI film. By changing the energy and dosage of ions, we investigate the zeta potential and surface tension variation of PI film implanted by H、He、C、N、Fe、Ti、Zr and Hf ions. The influence of implanted ions on the physicochemical properties of PI is analyzed. It is found that the surface zeta potential of ion implanted PI film has close relationship with surface lewis acidity γL+, which can be use to adjust the surface physicochemical properties of PI film. By changing the surface zeta potential with Fe ion implantation, we successfully realize the surface patterning of nano particles on PI films.

Resume : Multi-functional fluorocarbon plasma polymer thin films are fabricated on a large-area polyethylene terephthalate substrate using continuous roll-to-roll sputtering with a 700-mm film width. Carbon/polytetrafluoroethylene composite target is used for the mid-range frequency sputtering for the first time. They exhibit water-repelling surfaces to preventing wetting and to remove contamination. In addition, plasma polymer thin film shows high optical transparency because they have amorphous structure and relatively low optical constants. The maximum optical transmittance of the fluorocarbon thin films with a carbon concentration of 1 wt% is 93.27% at a 550 nm wavelength. The cross-linked carbon structure enhances the hardness and modulus of the fluorocarbon plasma polymer thin films. Surface hardness of the fluorocarbon plasma polymer thin film increases from 0.58 GPa (Carbon 0 wt%) to maximum 6.9 GPa when carbon or inorganic materials are incorporated into the PTFE composite target. The outer bending test shows remarkable mechanical flexibility characteristics with a minimum bending radius of 3 mm and excellent cyclic fatigue resistance. From these results, we confirm that a high hardness fluorocarbon thin film with high hydrophobicity, transparency and flexibility can be fabricated via mid-range frequency roll-to-roll sputtering.

Resume : Cellulose nanocrystals (CNCs), nanorods produced by acid hydrolysis of cellulosic sources, are emerging as a new class of functional biomaterial. CNCs present a broad range of uses, for example in composites, cosmetics, security paper and medical devices [1]. The fascinating ability of CNCs to self-organize into a cholesteric liquid crystal phase, with a helical arrangement of the nanorods, is attracting substantial interest across different research fields [2]. It is important from an applied point of view since this arrangement gives a photonic band gap to the final dried CNC films, but also from a fundamental soft matter physics perspective, as many details of the CNC liquid crystal formation are far from being understood. A critical problem from an analytical, and likely also from an applied perspective, is the high length polydispersity of as-produced CNC samples. In this study, we introduce a method for fractionating the CNC nanorods, utilizing the spontaneous phase separation between isotropic and liquid crystalline phases, allowing us to narrow down the length distribution. The aspect ratio (length/diameter) has a strong effect on the period of the cholesteric helix, affecting the iridescent colors appearing in dried CNC films. We believe that a reduced polydispersity will allow us to better control the color of the finally dispersed films, compared to the natural polydisperse samples that are now being used in the community. We present how this affects the self-assembly process, and consequently the color formation in such bio-derived structural films. [1] J.H. Park et al., ChemPhysChem, 15, 7, pp. 1477-1484 (2014) [2] Lagerwall, J. P. F. et al. Cellulose nanocrystal-based materials: from liquid crystal self-assembly and glass formation to multifunctional thin films. NPG Asia Mater. 6, e80 (2014).

Resume : There are many important applications for thin films in areas where there is a strong radiation field. It has been recently showed that thin films which are nanostructured would behave differently under irradiation than polycrystalline or single crystal films. The absence of a relatively long-distance order allows for very short diffusion lengths of irradiation generated defects towards grain boundary regions that act as sinks. Therefore, the structure and properties of such thin films should not be strongly affected by exposure to radiation. Also, dislocations could not exist in very small grains. Therefore, the increase of mechanical hardness after irradiation caused by the generation of arrays of dislocations that will become entangled and therefore immobile, could not be observed in these nanostructured films. To investigate in detail the radiation effects on properties and structure of such materials we used the Pulsed Laser Deposition (PLD) technique to grow nanocrystalline or amorphous thin films from inexpensive targets. By simply changing the deposition parameters, films possessing different chemical compositions and/or structures could be readily obtained. The effects of 800 keV Ar and 1 MeV Au ions irradiation on the microstructure, surface morphology and chemical composition of nanostructured ZrN thin films were investigated and the results compared to those obtained on polycrystalline or single crystal materials. Nanoindentation results clearly showed a significant decrease of hardness and Young modulus in irradiated ZrN films from the initial 35 GPa and 270 GPa to 15 and 160 GPa, respectively.

Resume : The necessity of providing direct microstructure evidence for the validity of the so-called colossal carbon supersaturation mechanism [1] as applied to the surface carburization of Inconel-718 (IN-718) superalloy [2] triggered the present research. We will present new microstructure findings revealing the nanostructuration of the uppermost surface layer of IN-718 alloy submitted to gas-carburization processing at low-temperature (< 600°C) by the standard procedure invented by Swagelok Co. Ltd. (USA) [3]. Our new results are showing that the mechanism of paraequilibrium diffusion of C atoms in the crystal lattice interstitial positions, up to colossal carbon concentrations and avoiding the carbides formation (LTCSS) is not the true mechanism of IN-718 surface properties modification. Instead, the nanostructuration of the alloy surface layer is revealed, due to the phase instability of initial surface grains in carburization gas atmosphere, an effect which probably occurs also in other similarly processed alloys. Some of the nanostructure features observed by means of HR(S)TEM and EELS were already communicated (see abstracts at [4]), but a comprehensive presentation of our research data will be done herewith. [1] Cao Y, Ernst F, Michal G, Acta Mater 2003; 51, p.4171 [2] Sharghi-Moshtaghin R et al, Metall Mater Trans A, 2010; 41A, p.2022 [3] Collins S and Williams P, Advanced Materials & Processes / September 2006, p.32 [4] https://www.researchgate.net/profile/Corneliu_Sarbu

Resume : We generate nanoparticles (NPs) using high-power pulsed hollow-cathode sputtering, yielding high productivity and simultaneously excellent control over NPs size and size distribution. The use of the high-power pulses is key to the success of the process, since it provides an efficient ionization of the sputter-ejected atoms. The positive metal ions are very effectively trapped on growing negatively-charged NPs, since NPs are negatively charged in a plasma. A range of materials has been synthesized including Fe, Cu, Ti, Ag, Mo, In and Zn. By adding a reactive gas to the process NPs containing Ti-O, Ti-N, Zn-O and In-N has been synthesized. Several process parameters were identified to affect the size, size distribution, shape and structure of the nanoparticles. These parameters include pulse power, pulse frequency, sputtering gas composition, gas pressure and geometry of the setup. By tuning these parameters, the nanoparticle size can range from a few nm to more than 250 nm in diameter. To fully utilize the synthesized NPs in applications, they often need to be positioned or assembled into complex architectures including nanowires (NWs), pillars, and surface patterns. Since the NPs are negatively charged electrostatic fields can be utilized for this purpose. For magnetic NPs, externally applied magnetic fields make it possible for the NPs to self-assembly into cross-linked NWs, reaching many micrometers in length while only one NP wide (20-60 nm) in the individual NW.

Resume : Herein we report the development of large scale, antireflective and anti-fogging coatings applied on windshields for automotive industry. Sol-gel based coatings were optimized to fulfill the strict requirements of a car environment. We showed that the pollution rate is a critical point to ensure a sustainable antifogging coating. The “fog effect” can be explained in terms of light scattering due to the formation of water microdroplets onto colder substrates. In most of the papers related to fogging, the macroscopic optical effect is simply associated to the static contact angle of water on the surface. In our work, we rely the macroscopic opacification to a microscopic observation of the nucleation, growth and eventually coalescence of microdroplets onto functional thin films. Computational models based on the Mie theory were then applied to support the experimental results. Interestingly, superhydrophilic TiO2 coatings are not efficient when applied in polluted environments. XPS measurements were performed to explain the role of pollutants accumulation onto the sol-gel layers. The effect of surface energy was further investigated by using other sol-gel coatings exhibiting controlled hydrophilicity/hydrophobicity ratio. Finally, a pre-industrial demonstrator on laminated glass was fabricated by dip-coating. The final material is able to combine the enhanced anti-fogging properties with the other requirements such as anti-reflectivity, colorless and mechanical stability.

Resume : The scarcity of raw elements and the environmental implications of employing hazardous materials in technology have intensified the demand for sustainable and cost-effective alternatives. The Fe–Cu system presents an attractive option due to its wide availability, eco-friendliness and highly tunable magnetic properties. Among the various methods utilized to produce metallic films, electrodeposition is an appealing technique due to its low cost, simple set-up, operation in ambient pressure, fast deposition rates on a variety of substrate geometries and ability to grow fairly thick, homogeneous coatings. Existing literature on electrodeposited Fe–Cu films, however, is limited due to the immiscibility of Fe and Cu and the tendency to form oxides/hydroxides during deposition. Furthermore, film properties depend heavily on fabrication method and experimental conditions. In this work, FexCu1-x continuous films with minimized oxygen content were deposited over a wide composition range (0≤x≤86) from three electrolytes where the complexing agent was altered. The effect of electrolyte composition and plating parameters on the stoichiometry, morphology, structure and magnetic properties of the films was investigated. In a subsequent step, hierarchically porous FeCu films were produced using electrodeposition through colloidal templates (with nanospheres of 200nm, 350nm and 500nm) with a focus on the effect of nanosphere size network characteristics on wettability and magnetic behavior.

Resume : Stem cells are extensively studied due to their unique properties and great potential in biomedical applications [1]. Thanks to a variety of biological responses, metal-oxide coatings are widely used for interacting with stem cells [2, 3]. A very limited number of oxides have however been studied, and mechanism of the cell-material interaction is still not completely clear. Here, oxides thin films, that are well-known for their electronic properties, are deposited on substrates using the pulsed laser deposition (PLD) technique. Bone marrow mesenchymal stem cells were cultured on the surfaces of thin films and their adhesion, proliferation and differentiation were evaluated as a function of the growth conditions, thickness of the films, surface roughness and morphology. These results will be of a great clinical significance, in particular, in the field of regenerative medicine. M.K. thanks support from Normandie Université for her PhD fellowship. Partial support from project Emergence Normandie, and the FEDER are also acknowledged. References: 1. Bianco, P., Robey, P.G., 2001. Stem cells in tissue engineering. Nature 414, 118–121. 2. Gittarda, Sh. D., Perfect, J. R., Monteiro-Riviere, N. A., Wei, W., Jine, Ch., Narayan, R.J., 2009. Assessing the antimicrobial activity of zinc oxide thin films using disk diffusion and biofilm reactor. Applied Surface Science 255, 5806–5811. 3. Zhang, S., Sun. J., Xu, Y., Qian, S., Wang, B., Liu, F., Liu, X., 2012. Biological behavior of osteoblast-like cells on titania and zirconia films deposited by cathodic arc deposition. Biointerphases 7, 60–70.

Resume : The stainless-steel based bipolar plate is one of key component of recent polymer electrolyte membrane fuel cells. Due to the low electrical conductivity and insufficient corrosion resistance of stainless-steel, the adoption of coating process is essential for the efficient protection. Despite of the extensive efforts, critical challenges still remain in finding an adequate protective coating material and method, which satisfies the strict requirements. Here, we demonstrate that a high degree of corrosion protection and electrical conductivity of stainless-steel 316L (SS316L) based bipolar plate can be achieved by simply adopting ultrathin (25~67 nm) plasma-enhanced atomic layer deposition (PEALD) of TiN thin films. For this, we carefully evaluated two types of TiN protective coatings prepared by PEALD using tetrakis-dimethylamido-titanium (TDMAT) and titanium tetrachloride (TiCl4) precursors in environments simulating the bipolar plate situation. Regardless of the precursor types, the adoption of PEALD-TiN on SS316L exhibited great improvements in the electrical conductivity and corrosion resistance. Noteworthy, TiN thin films using TDMAT exhibited an excellent corrosion resistance (<1 μA/cm2) than that using TiCl4 precursor. A systemic structural, compositional, and electrochemical analyses reveals that ~5nm-thick ultrathin amorphous interfacial layer, formed when TiN thin films were prepared using TDMAT, played a key role in the corrosion protection. Furthermore, TiN thin films using TDMAT greatly lowered the interfacial contact resistance of SS316L.

Resume : Adhesion at alumina/zinc interfaces is one of the key issues in steel manufacturing industries. Indeed, while enrichment in elements, such as Al, improves the strength of new steel grades, the selective oxidation of Al may lead to the formation of a quasi-continuous alumina film at the steel surface, which dramatically reduces Zn adhesion strength. It has been shown that transition metal buffers considerably enhance adhesion of the weakly interacting alumina/zinc interface. However, oxidation of such metal buffers has an overall detrimental effect. In the present study, we consider more complex, stainless steel buffers at the alumina/zinc interface. The buffers consist of several metals (M = Cr, Fe, and Ni) and/or of their oxides depending on oxygen conditions and are represented by the corresponding sequence of interfaces. We performed ab-initio simulations to calculate interface and adhesion energies of all interfaces between each two materials. Monte Carlo Metropolis simulations were employed to find the most stable interface sequences in the complex buffer. We analyze the spatial distributions of materials and interfaces in the complex buffers and identify points of weakest adhesion. Our results clearly show that regardless the oxidation conditions, stainless steel buffers produce good adhesion properties which make them promising candidates to improve the adhesion of Zn coatings in the case of Al-enriched steel grades.

Resume : Because most of the biological reactions take place at the surface level, the implant surfaces play an important role in tissue engineering. Modification of the structure and surface chemistry of an implant can be achieved by various methods, the most commonly used being coating of the implant’s surface by biocompatible layers. Surface modification of titanium implants for bone contacting applications is a very active field of research in tissue engineering. In this research, the hydroxyapatite-collagen-silver coatings have been deposited onto titanium implants by a combined method involving hydroxyapatite/collagen electrochemical deposition, combined with silver ions reduction and in-situ crystallization processes on titanium surface. The electrolytic processes implies the nucleation and growth of hydroxyapatite crystals on the surface of the titanium implant in a simulated body fluid under physiological conditions of pH and temperature, applying a constant current for different periods of time. The collagen has been used to modify titanium surfaces in order to enhance their bioactivity. The silver incorporation into hydroxyapatite coatings is an alternative that can provide good antibacterial properties of these coatings. The morphology, composition and phase structure of the hydroxyapatite-collagen-silver coatings were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD).

Resume : There is a theoretical prediction that normal ferromagnetic fcc cobalt, when compressed to a high density, is likely to have a nonmagnetic phase[1]. In a polycrystalline thin film, the presence of compressive stress can lead to an increase of material density [2]. We have searched for a high density nonmagnetic phase of cobalt in a polycrystalline cobalt thin film and we have succeeded in obtaining the experimental evidence of formation of high density (HD) nonmagnetic cobalt[3]. We have prepared a 25 nm cobalt (Co) thin film on HF etched clean Si(111) at room temperature under high vacuum by e-beam evaporation. We then exposed the film to air due to which about 3 nm cobalt oxide forms on the top of the film. After a sufficiently long time we have carried out X-ray reflectivity (XRR) and polarized neutron reflectometry (PNR) experiments at Bhabha Atomic Research Centre, Mumbai, India. The PNR experiment is repeated at Oak Ridge National Laboratory, Oak Ridge, USA and we have obtained the same results with better precision due to large neutron flux. From XRR fit shown we observed a very high density (HD) layer (high scattering length density) of cobalt at the Co/Co-oxide interface and at the Co/Si interface. Only after considering these two high density layers we get the best fit to the XRR data. From PNR we have corroborated the existance of these HD layers and additionally the PNR data fit shows that these high density Co layers have nearly zero magnetic moment. Cobalt in the mid depth region of the film i.e, between these two high density layers has normal density and magnetic moment. Rutherford back scattering spectrometry experiment has ruled out the presence of any element of higher atomic number than Co. This has confirmed that the HD material is indeed Co. Further we have carried out planar TEM, XTEM, HRTEM, HAADF, EDS, EELS measurements. All these results confirm the formation of high density cobalt within the Co thin film and shows that this HD phase of Co has an fcc lattice structure. From HRTEM in planar view we get an fcc lattice constant of Co which corresponds to 30% of volume reduction (density enhancement) compared to normal Co. Theory predicts an fcc nonmagnetic Co with 1.4 times density of normal hcp cobalt [1]. Our observed HD Co has a density in the range of 1.2-1.4 times the normal Co density. Further results on the dependence of nonmagnetic HD Co formation on the film thickness, capping and substrate will be presented. References: [1] S. F. Matar et al, Phys. Rev. B 75, 245109 (2007). [2] E. Chason et al, Phys. Rev. Lett. 88, 156103 (2002). [3] Nasrin Banu, Surendra Singh, B. Satpati, A. Roy, S. Basu, P. Chakraborty, Hema C. P. Movva, V. Lauter and B.N. Dev, Scientific Reports (in press).

Resume : Fiber-reinforced composite materials find applications in a wide range of fields such as automotive industry for the development of lightweight vehicles [1]. While such materials could provide enhanced mechanical properties, poor polymer matrix-fiber interactions could be detrimental. Various approaches were envisaged to overcome this issue through the treatment of the fibers or addition of agents promoting an enhanced dispersion of the fibers in the polymer matrix [2]. Here supramolecular interactions are being exploited. Sequence-defined oligomers based on amino acids and spacing units were prepared by solid-phase synthesis [3] using phenylalanine as amino acid to promote interactions with aramid fibers. A library of sequence-defined oligomers was synthesized to identify the structural features necessary to obtain compatibilizers leading to fiber-reinforced composite materials of high performances. Their thermal behavior and adsorption on aramid fibers were investigated to evaluate their potential viability to the processes used in the automotive industry and capability to promote compatibilization. 1. (a) Brosius, D., SPE Automotive Composite Conference: proceedings of a conference, 2003,1-7; (b) Chopade S.B. et al., Int. j. innov. res. sci. eng. technol., 2015, 4(1), 18801-18808 2. (a) Saheb D. N et al., Adv. Polym. Technol. 1999, 18, 351-363; (b) Mukhopadhyay S. et al., J. Thermoplast. Compos. Mater. 2003, 16, 479-495 3. Chan-Seng D. et al., ACS Macro Lett. 2014, 3, 291-294

Resume : Much research has been devoted to exploring potential advantages of a thermoplastic matrix for composite materials. Such matrix is polyaryletheretherketone (PEEK) which exhobits exceptional properties due to its semicrystalline character and the molecular rigidity of its repeating units. PEEK materials are semicrystalline aromatic polyesters with excellent mechanical and dielectric properties. PEEK has good chemical resistance. However, a potential clinical disadvantage of intervertebral disc implants, is that PEEK alone is not bioactive. Surface functionalization of medical devices made of polyaryletheretherketone (PEEK) is an essential requirement when a direct osteointegration between implants and host tissues is desired. The main objective of the work was to improve bio- activity and tribological properties of advanced polymer PEEK type materials through development of biomimetic, smart polytetrafluorethylene (PTFE) composite coatings. The optimal biological and tribological properties of the PTFE coating were found for porous, nano- composite, multi- layered structures. Coatings were porous on the surface, which was prone for fibroblast cell proliferation, and more dense close to the PEEK substrate, what positively influenced on their tribological properties. Acknowledgment: This work was supported by the National Science Centre (Narodowe Centrum Nauki, abbr. NCN) No: 2014/15/B/ST8/00103

Resume : In this paper, we describe a developed and characterized liquid precursor delivery system (LDS) for preparation of a water-vapor permeation-barrier layer in organic electronic devices. The proposed LDS consists of three major parts: 1) an aerosol generator that transforms the liquid precursor into an aerosol molecule by a piezoelectric ultrasonic vibrator, 2) a vaporizer that transforms injected aerosol molecules into a vapor state, and 3) vapor storage canister. The instant evaporation fraction and maximum evaporation mass rate were measured to be 98.3% and 2.55 g/min, respectively. The temperature in the vaporizer was very stable, showing only 1oC of a difference from the set temperature. As the temperature in LDS increased, the evaporation mass rate increased from 0.035 to 2.55 g/min. A 30-nm-thick SiN layer was prepared to evaluate the performance of LDS, which was attached to a cyclic-chemical vapor deposition system. The prepared SiN layer exhibited a very smooth surface with no defects and pinholes. The roughness of the prepared SiN film was measured to be 1.25 nm in the root mean square value, which is comparable to conventional bubbler type LDS. The water vapor transmission rate obtained from the 30-nm-thick SiN layer was measured to be 1.31×10-6g/m2/day. That measurement meets the requirement for organic electronic device applications, such as organic thin-film transistors, organic solar cells, and organic light-emitting diodes.

Resume : Droplet-based microfluidic systems have received broad attentions since they allow sufficient chemical and biological analyses with only small amount of specimen and reagents. Compared to the continuous flow-based microfluidics, which need complicated channel networks, droplet-based microfluidic systems can supply more versatility. Recently, novel droplet-based microfluidics have been developed using superhydrophobic surface, enabling the droplet manipulation without any additives. However, despite its advantage, it still has limitation to manipulate the low-surface tension liquid, which prohibits the application of diverse bioassay. Herein, we developed the new class of droplet manipulation platform using flexible superomniphobic substrate and local vacuum suction device. Flexible superomniphobic substrate was made by spray coating of fluorinated SiO2 nanoparticle. When the negative pressure was applied below the substrate by using the vacuum tip, local dimple was generated. Since adhesion force between the substrate and the droplet there was very small, the droplet can be guided in the local dimple by the gravitational force. In addition, we demonstrated a few micro-litter droplet patterning technique using fabricated system with partial superhydrophilic patterning. Based on the system, we could precisely analyze the concentration of glucose in a sample droplet. This platform may give a chance to proceed the bioassay area and may be used in diverse experiments such as chemical synthesis and colorimetric multiplex bioassay.

Resume : The aim of this study is to provide HA-ZrO2 ceramic coatings on 316L stainless steel and titanium by cathodic plasma electrolytic deposition technique and to investigate it’s biocompatibility in artificial saliva and Ringer’s solution. The process was performed in K2ZrF6 electrolyte solution. The surface layer chemical compositions were analyzed by X-ray diffraction (XRD) and it was shown the formation HA-ZrO2 on the substrates. Scanning electron microscope (SEM) was used to observe the unique morphology of the surface layers. The corrosion resistance of the coated surface was investigated by electrochemical studies involving cyclic voltammetery method in artificial saliva and Ringer’s solution. The results showed a corrosion resistance improvement due to the variation in composition and unique surface morphology. Wear resistance and friction coefficient were investigated using pin on disc wear test. The unique morphology of the surface layer caused the improvement of wear resistance and friction coefficient. Also Roughness and hardness of the samples were measured. The results indicated the significant increasing effect of PED treatment on the surface roughness and hardness. With analogy between the results, it can be concluded that HA-ZrO2 coated 316L stainless steels are good substitutes for titanium in implantology for manufacturing osseointegrated implants like hip and knee replacement, shoulder and elbow joints replacement and also dental implants.

Resume : Nowdays, the development of functionalized nanoparticles has an important growth, because of their future possibilities and applications in cancer treatment. Functionalized magnetite nanoparticles can be used as magnetic domains core with an organic bicompatible shell to add complex systems. In this work, magnetite nanoparticles have been synthesized with different batches, via co-precipitation at 80°C from ferrous Fe(2) and ferric Fe(3) ions, under an inert atmosphere. In one of the batches, during the synthesis, 3-amino-1-propanol was used as a reducing agent and stabilizer. In the other synthesis, the magnetite nanoparticles were aminated through silanization, using 3-aminopropyltriethoxysilane (APTES), as linker. The amine-magnetite nanoparticles enable the covalent conjugation of a paramagnetic gadolinium complex Gd- diethylenetriaminepentaacetic acid (DTPA). The surface of these nanoparticles was functionalized with (DTPA) via carbodiimide chemistry; where the DTPA acts as complexing agent for the introduction of gadolinioum ions on the surface of the nanomaterial. Morphology, particle size, structure and magnetic properties of the as-prepared nanocomposites were charcaterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman Spectroscopy, Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), Fhotoluminiscence and Magnetic Force Microscopy (MFM) to define their physical properties as contrast agents.

Resume : Fluoropolymers are increasingly used for the mass production of microoptical elements as they are sufficiently stable, reliable, UV transparent materials and can replace the expensive quartz, for example, producing microlenses. In this study, UV nanoimprint lithography using rigid polymer molds was succesfully applied for the patterning of microlenses in OrmoComp polymer layer drop-deposited on the ETFE and FEP fluoropolymers substrate. Adhesion of ETFE and FEP fluoropolymers surface was significantly improved using H2 plasma treatment for 1-3 min at RF source power density of 0,5 W/cm2 under operating pressure of 1.3 Pa and hydrogen flow rate of 100 standard cubic centimeters per minute (sccm). The surface energy of H2 plasma treated ETFE and FEP fluoropolymers increased substantially, thus significantly enhancing the wettability and adhesion properties. Aging tests show, that H2 plasma treatment of fluoropolymer films have long-term effect and does not cause any defects, affecting behaviour of microlenses.

Resume : Dental frameworks made of ceramic veneered CoCr alloy are widely used in dentistry due to their superior mechanical properties and favourable aesthetics. However, their clinical performance is affected by the biological environment leading to partial removement of the ceramic layer, leaving larger areas of metal exposed to the aggressive oral environment. We report on three multilayers (CrSiN/CrSiON, CrSi/CrSiN/CrSiON and Cr/CrSi/CrSiN/CrSiON) obtained by cathodic arc method and used to overcome the failure of dental prosthesis by improving the bond strength between CoCr framework and ceramic component. An overview on the behaviour of the coated CoCr alloy was carried out by in vitro studies in simulated body fluids, from both corrosion and biocompatibility points of view. The results indicated that the protection efficiency increases with the number of interfaces, blocking the penetration of the electrolyte through the pores of the coating. Cell viability was found to be high for all the coated samples. During 3-points bending tests the coated Cr/CrSi/CrSiN/CrSiON substrates of CoCr covered with dental ceramic exhibited the best behaviour, associated with the coatings' highest surface roughness and hydrophilicity. This finding can be related to the presence of Cr layer at the CoCr interface, which provided a better adhesion by superior chemical affinity. We acknowledge the support of the Romanian Research and Innovation Ministry, projects PN 16.40.01.02, PN 16.40.01.01.

Resume : Atomically thin molybdenum disulfide (MoS2) has attracted extensive attention because of its remarkable mechanical and electronic properties, and low friction characteristics. Raman spectroscopy has been widely used to characterize the thickness and the thickness-dependent material properties of atomically thin MoS2 owing to the sensitivity of the vibrational spectrum to the thickness. However, the focused laser may increase the surface temperature, which in turn results in surface damage on the upper layers of the MoS2. This laser-induced thermal effect can further influence the aforementioned material properties. In this work, the effects of laser on surface of atomically thin MoS2 were systematically investigated using atomic force microscopy (AFM) and Raman spectroscopy. Single and a few layers MoS2 flakes were prepared by mechanical exfoliation and they were treated by lasers with various powers. AFM topography and friction force images were obtained before and after laser treatment. The result showed that particles were formed on the top surface of MoS2 due to the laser-induced thermal effect. It was also found that degree of the particle formation was dependent on the laser power and the thickness of MoS2. Furthermore, the particle formed on MoS2 surface caused the significant increase in friction force. The outcomes of this work may be useful for the thermal management in the design of nano-devices based on atomically thin MoS2.

Resume : The development of new bio-compostable materials has attracted much attention in the field of food packaging. However, the main drawback of biodegradable films is the low barrier they offer against external agents that can quickly degrade foods, limiting their use to a small number of products. To overcome this issue, we developed a new active multilayer film, bio-compostable with excellent oxygen scavenging proprieties, able to increase the shelf-life of food products obtained without the use of preservative agents. The oxygen scavenging activity is obtained by including in the multilayer film system a layer of glucose and glucosidases that catalyzes the oxygen absorption. Both molecules and enzyme are dissolved in a polymer matrix based on PVOH and deposited on a PLA film, following an appropriate treatment with plasma to increase the hydrophilicity, allowing a uniform coating. The plasma treatment is performed in air with an in-line reactor chamber included in the film-forming machine. The main effect is to increase the number of alcohol and methyl groups, enhancing the contact angle and guaranteeing a perfect coating with the active gel solution. In order to monitor the efficiency of the innovative active packaging a sensor based on a conductive polymer has been developed, that, used as an ink, is stamped on the PLA surfaces after the plasma treatment. The final PLA multilayer film with high oxygen scavenging activity, being totally biodegradable, can perfectly implement a “green” food packaging.

Resume : One problematic aspect of graphene (GR) CVD growth on metal substrates is that GR is capable to create rotational domains [1], separated by grain boundaries (GBs), sometimes even on a single crystal surface [2]. GBs worsen the electric properties of GR[3], therefore the nucleation of differently orientated islands is an undesirable phenomenon. An interesting feature is, that the different existing orientations are very specific to the substrate (e.g: on Cu(111) the most commonly known orientations are: R0°, R7°, but for Ir(111) we have R0°, R14°, R19°, R23°, R26°, R30°)[4]. Even today there is no such a physical model that can somehow clarify the very basic nature of these orientations. Why only these orientations can appear, and what are the circumstances that influences the GR to realize one or another? In order to understand these aspects we developed a continuum mathematical model that calculates the adhesion energy of a GR island with a given size and orientation only by knowing the underlying Moiré-pattern that is formed between the atomic lattices. Our model agrees surprisingly well with DFT and CMD results. This shows that we have captured some very basic physical insights of the adhesion. Using our model Monte-Carlo (MC) simulations can be carried out to perform GR growth simulations on several germs to analyze their distribution of orientation. These MC simulations are several orders of magnitude faster than Kinetic MC methods. References: [1] M. Batzill, Surf. Sci. Rep. 67, 83 (2012). [2] Li Gao, Jeffrey R. Guest, Nathan P. Guisinger, Nano Letters 10(9), 3512-3516. (2010). [3] Vancsó, Péter, et al., Applied Surface Science 291, 58-63 (2014). [4] Tetlow, H., et al., Physics Reports 542.3, 195-295 (2014).

Resume : The growth of carbon nanotubes (CNTs) on polycrystalline silicon substrates was studied to improve the design of CNT field emission sources for microelectromechanical systems (MEMS) applications and vacuum microelectronic devices (VMDs). Microwave plasma-enhanced chemical vapor deposition (PECVD) was used for CNT growth, resulting in CNTs that incorporate the catalyst particle at their base. The kinetics of CNT growth on polysilicon were compared to growth on Si (100) using the model of Deal and Grove, finding activation energies of 1.61 and 1.54 eV for the nucleation phase of growth and 1.90 and 3.69 eV for the diffusion-limited phase on Si (100) and polysilicon, respectively. Diffusivity values for growth on polysilicon were notably lower than the corresponding values on Si (100) and the growth process became diffusion-limited earlier. Evidence favors a surface diffusion growth mechanism involving diffusion of carbon precursor species along the length of the CNT forest to the catalyst at the base. Explanations for the differences in activation energies and diffusivities were elucidated by SEM analysis of the catalyst nanoparticle arrays and through wide-angle X-ray scattering (WAXS) of CNT forests. Finally, methods are presented to improve adhesion of CNT films during operation as field emitters, resulting in a 2.5x improvement.

Resume : Semiconductor heterostructures are widely used in device fabrication. A lot of modern transistors, lasers and solar cells are manufactured using heterojunctions. Portable optoelectronic gas sensors operating in the IR spectral range are already replacing conventional electrochemical monitors. In general the gas is pumped into the chamber and gas concentration is measured electro-optically by its absorption of a specific wavelength. Such sensors can be used to determine a lot of gases including chlorine. It is an important component in the manufacture of conventional materials. At the same time chlorine is a toxic gas that attacks the respiratory system, eyes, and skin. Thus it is very important to measure chlorine concentration in air and aqua solutions. It is known that chlorine gas and its oxygen compounds in solution absorb light in the wavelength range of 300-420 nm [1]. ZnO based photodetectors have a similar spectral range [2]. The combination of UV LED with a ZnO based photodiode can be used in low-cost chlorine sensor. This paper presents some results obtained from an investigation of growth parameters on EQE spectra of ITO/ZnO/Cu2O heterostructure made by magnetron sputtering. A sensitive and low-cost free chlorine sensor has been developed and sensing tests were performed. The reported study was supported by RFBR project №15-08-06645a. [1] Rafaela T.P. et al. // J. Braz. Chem. Soc., 2012. V.23, P.1543-1550 [2] K. Liu et al. // Sensors (Basel). 2010; 10(9): P.8604–8634

Resume : Studies of thin nanocluster films of Mo, Ag, Ta are of great interest due to their possible applications as highly efficient thermoelectric materials. In this work thin nanocluster films of Mo, Ag and Ta were formed on SiO2/Si(001) surface at room temperature using nanocluster source Nanogen-50 with quadrupole mass-spectrometer MesoQ (Mantis Deposition, UK) incorporated into the UHV surface analysis system Multiprobe MXPS VT AFM (Omicron NanoTechnology GmbH, Germany). The chemical composition of thin nanocluster films was controlled in situ by means of X-ray photoelectron spectroscopy. Susceptibility of the films to oxidation was studied ex situ at room temperature and after heating up to 900 K. The size and shape of the clusters in films were measured ex situ by analyzing images obtained with the scanning electron microscope. The band gap value for Ta, Mo films were measured using reflection electron energy loss spectroscopy. Variation of the work function of the films with size of clusters in film were studied. Electronic and chemical properties of films obtained show the potential of further usage of nanocluster films as thermoelectric materials.

Resume : Results of experimental studies of thorium ions implantation into thin silicon oxide layers within pulse plasma fluxes expansion are presented. Formation of plasma plumes were initiated in solid-state thorium target in strong electrical fields by nanosecond laser pulses with power density of about several GW/cm2. Depth distribution of thorium atoms in the subsurface area of 10 nm thickness, chemical state of implanted thorium atoms and bandgap of modified silicon oxide film at different conditions of implantation processes were studied with XPS and REELS methods. The results of chemical composition analysis of the surface with XPS and REELS methods show that the compounds obtained in modified silicon oxide film are based on a complex thorium silicates and have bandgap within a range of 6.0-9.0 eV depending on local concentration of thorium atoms. A quantitative assessment of the yield of isomeric nuclei in a “hot” laser plasma at the early stages of expansion was made. The estimations made again with experimental results show that the laser ion implantation of thorium ions in SiO2 matrix can be useful for further research of «nuclear clocks» based on low-lying isomeric transition in 229Th isotope with energy 7.8 ± 0.5 eV.

Resume : Superconductor ferromagnet hybrid structures, which shows different, coupling mechanisms in the interface, have promising applications in spintronics. Generation of spin triplet cooper pairs and longer spin relaxation time in superconductors enables efficient spin injection and dissipation less spin transport. Bi and tri layers of FM/SC/FM structures showed exchange couplings and giant magneto resistance (MR) below their Tc. CoFeB/MgO/CoFeB based magnetic tunnel junctions with its interfacial epitaxy and formation of crystalline interface showed record TMR at room temperatures. Exploiting this interfacial quality, which is responsible for high spin filtering can be used for fabricating CoFeB/MgB2 based hybrid layers. MgB2 superconductor with industrially acceptable critical current density is an excellent choice because of its oriented growth over MgO substrates. We have fabricated CoFeB (100nm)/MgB2 (50nm) hybrid structure through DC sputtering and pulsed laser deposition respectively. This structure has been annealed at 573K to achieve epitaxial formation at CoFeB/MgB2 interface. XRD and XRR measurements showed oriented formation of MgB2 formation over CoFeB and respective thicknesses. Magnetic measurements were done to extract Jc values from Beans extended critical state model. We will discuss in detail about the magnetic properties of CoFeB/MgB2 hybrid structure, which will enable us to fabricate CoFeB/MgB2/CoFeB structure for spin injection and MR studies

Resume : In this study, zinc sulfide(ZnS) thin films were fabricated using a wet chemical process. ZnS thin films were analyzed according to the addition of a complexing agent, the characteristics of ZnS thin films were analyzed by adding EDTA(ethylenediamine tetra-acetate acid), HMTA(hexamethylene tetramine). The morphological characteristics of the ZnS buffer layer are closely related to the use of a complexing agent that controls the concentration of Zn2+ ions in the deposition process. The addition of the complexing agent EDTA accelerated the cluster - cluster method, resulting in faster deposition but lower uniformity and greater cracking phenomenon. HMTA can be effectively applied to increase the amount of Zn2+ ions forming ZnS. it is easily found as Zn2HMTA at high temperatures. The results of the experiment with the addition of HMTA revealed that as the HMTA concentration increased, the surface of the thin film did not change, but the thickness of the thin film increased gradually. HMTA promoted the ion-ion method to grow the thin film uniformly, but the speed was slow. Additionally, experiment with mixed complexing agent was executed. The best ZnS thin film with transmittance of 80.7%, denser surface was prepared by mixing and adding EDTA and HMTA at an HMTA concentration of 0.2 M. However, as the concentration increased, the growth rate of the thin film increased. However, the surface cracked too much to be used as a buffer layer.

Resume : Many efforts have been made to improve the surface properties of copper, a material with many applications such as electrical wires and industrial machinery and alternators which are based on copper thermal and electrical conductivity, its malleability and ductility. However, the main disadvantage of copper is its poor oxidation resistance especially at elevated temperatures. The scope of this work is the comparative study of Mg, Al and TiN coatings deposited on commercial copper for the improvement of the surface resistance when exposed in harsh environment. In every case the deposition was accomplished by pack cementation which is a promising low cost and environmental friendly method. It is a thermochemical process which combines a chemical vapor reaction and the solid state diffusion step. The experiments were undertaken at temperatures from 500 to 600ο C for Mg and Al and from 850 to 1000ο C for TiN coatings, while the holding time was 2h in every case. The structure of the coatings was examined with X-Ray diffraction, X-ray photoelectron spectroscopy and electron microscopy. Selective specimens were examined for oxidation resistance by thermogravimetric analysis and for surface hardness by nanoidentation. It was revealed that in every case thick uniform coatings were formed which were found to offer improved oxidation resistance under high temperature air exposure. Finally TiN coatings were revealed to increase the surface hardness of the Cu coupons.

Resume : Surface acoustic waves (SAW) devices are key components in communication systems. They are also intensively studied as wireless sensors, especially since they have demonstrated good operability in harsh conditions. Because of their unique combination of high acoustic velocity, large electromechanical coupling and good stability in harsh conditions, ScxAl1-xN thin films are highly valuable for various SAW applications. The aim of this work is to achieve highly-textured c-oriented ScxAl1-xN thin films, with a FWHM rocking-curve below 1° to maximize the piezoelectric properties of the film, for various Sc rates (0 ≤ x ≤ 0.4). The films are deposited by reactive magnetron sputtering on sapphire substrates, with a composite target. The microstructure is determined by θ-2θ, rocking-curve and pole figure X-ray diffraction (XRD) measurements. Transmission electron microscopy is used to observe the nanostructure, and the atomic ratio is measured by Energy dispersive X-ray spectroscopy. Firstly, AlN thin films with a strong (002) orientation (mosaicity < 0.5°) were deposited to get a reference sample without Sc. Then, the deposition parameters were adjusted to grow highly-textured c-oriented Sc0.07Al0.93N and Sc0.14Al0.86N films. XRD measurements show a strong (002) orientation for both compositions with a mosaicity below 0.9°. TEM micrographs show epitaxial growths at the substrate interface. Ongoing experiments are dedicated to the optimization of the film texture for higher Sc rates.

Resume : The feature of coatings for bone and dental implants is the ability to link with living bone. There is appropriate strengthening of coatings, using carbon nanotubes (CNT), which also show high rates of biocompatibility, and final laser surface treatment of finished implant to obtain such properties as strength, surface finely porous and corrosion resistant layers. The CNT were grown on a substrate of silicon oxide using the modified method of Cathodic Arc Evaporation. There was used a metal catalyst (Fe) to fix the carbon nanotubes on the substrate surface. Diameter of nanotubes on the surface of SiO2 is 15 - 25 nm. There were used such binders as glycerin, polyethylene glycol (PEG) and Vaseline to consolidate hydroxyapatite on the surface of the plate. These compounds are organic. There are carbon and hydrogen, elements that form the basis of biological fluids and tissues, in their chemical composition. There was done trial laser alloying to determine which of the agents is the best for this type of treatment. The best results shoved Vaseline. In this environment hydroxyapatite melted well and was uniformly covered on the substrate surface. There was held laser alloying of the surface with different energies (from 1 J to 5 J) of laser beam to get the desired properties of the coating and to prevent the overheating of the surface material. In the case of the laser beam with the energy E = 1 J hydroxyapatite melts well and evenly covers the surface of the base material. The thickness of hydroxyapatite layer was 100 microns.

Resume : Attributed to their high mobility and low temperature process, amorphous metal oxides have replaced silicon as main semiconductor materials in the thin-film transistors (TFTs). In AOS (amorphous oxide semiconductor) TFTs, the existence of sub-gap states plays an important role in electrical performance. In previous studies, the density of acceptor-like states (gA(E)) could be extracted from multi-frequency C-V and density of donor-like states (gD(E)), in other hands, is obtained by fitting I-V curves. In this study, we will get both gA(E) and gD(E) simultaneously, based on optical response of C-V characteristics of TFT. The C-V data of AOS TFT obtained under dark and light (532 nm) illumination are modeled separately in two gate voltage regions. For the gate voltage larger than flat band voltage, the TFT device acts as two capacitors in series (capacitance of active layer and dielectric layer) and the capacitors are extending from source to drain. However, for gate voltage smaller than flat band voltage, the capacitors are formed only for the area right under source/drain electrodes. With these two different models, gA(E) and gD(E) can be acquired; therefore, the energy-dependent sub-gap state profile is obtained simply by fabricating a TFT device.

Resume : Thin film metallic glasses (TFMG) has recently emerged as alternative materials for many applications, such as micro-electro-mechanical systems, micro- or nano-replication and biomedical use [1,2]. Physical vapor deposition (PVD) techniques like magnetron sputtering make possible synthesis of TFMG in an extended range of compositions. It has for example been demonstrated that binary Zr-Cu films [13-85 at.%Cu], presenting a glassy-like microstructure, can be obtained using pure Cu and Zr targets [3]. In this study, we focused on the ability to form TFMG from binary Zr-Ag, binary Zr-Cu and ternary Zr-Cu-Ag systems using PVD magnetron co-sputtering processes. Both static and rotating substrate holder configurations were performed for the three systems. The chemical composition of the films was obtained by energy dispersive X-ray spectroscopy, the structure was characterized by X-ray diffraction and the microstructure by scanning electron microscopy. In the static configuration, the composition of the films can be associated with the substrate position relative to the targets, while it can be controlled by the current applied to the targets in the rotating configuration. The influence of process configuration and composition on the structure and microstructure of the thin film was investigated. [1] J.P. Chu et al., Thin Solid Films 520 (2012) 509-5122 [2] A. Etiemble et al., J. Alloys and Comp. (2016) [3] M. Apreutesei et al., Thin Solid Films 561 (2014) 53-59

Resume : Hydroxyapatite (HAP) coatings are applied on Ti6Al4V metallic substrate to combine mechanical property of Ti6Al4V alloy with bioactivity property of HAP. In this study, HAP coatings with additions of SiC and Mg are proposed to be deposited on Ti6Al4V substrates by RF magnetron sputtering technique in order to improve the mechanical properties and to decrease the dissolution rate in simulated body fluid (SBF) of undoped HAP. Chemical bonding, morphology, mechanical and biological properties, corrosion resistance and degradation rate in SBF at 37 °C of the coated surfaces were evaluated. It was found that the SiC and Mg addition does not influence the formation of a stoichiometric structure of the HAP. All coatings exhibited smooth surface and uniform growth, without defects or cracks. The elastic modulus of doped coatings has a value more closely to those of human bones. The doped HAP coatings were found to enhance the corrosion resistance of the Ti6Al4V alloy in the SBF solution. The best corrosion resistance was found for the coatings with a smooth surface. A significant decrease of the mass loss rate of the Ti6Al4V alloy after coatings was found. The doped coatings have low degradation rate compared to uncoated substrate and undoped HAP. All of the investigated coatings were biocompatible as demonstrated by SaOS-2 bone cells attachment and growth. However, proliferation and morphology of cells grown on the coatings was somehow inferior than on uncoated Ti6Al4V.

Resume : Ti1?xAlxN coatings with NaCl-type structure have been widely used in advanced machining and other high temperature applications due to their excellent mechanical, thermal and tribological properties. Here, we investigated the influence of Cr additions on the structure, mechanical properties and oxidation resistance, including the oxide scale characterization, of multilayered TiAlN/CrAlN coatings deposited by magnetron sputtering. The properties of Cr rich coatings were compared to a TiAlN film deposited as reference. XRD diffraction analysis revealed that all coatings showed an fcc NaCl-type structure. However, for the TiAlN monolayer Ti and Al are forming a solid solution whilst, for Cr rich coatings, a multilayer structure alternating TiAlN and CrAlN layers, also forming solid *Manuscript Click here to view linked References solutions, was grown as a result of the geometry of the targets distribution inside the deposition chamber in combination with a slow rotation of the sample holder and a sufficiently high deposition rate. TGA measurements showed that Cr additions increased the oxidation performance of the coatings. For Ti0.47Al0.46N, dual oxide layers occur when tested at 800 ºC, being the porous inner one of TiO2 and the outer a compact and continuous layer of Al-oxide which protects the coating from the oxidation. At 900 ºC the oxidation resistance of this film degraded due to the fast Ti ions diffusion to the surface which impedes the formation of the continuous and protective Al oxide layer. Cr rich coatings showed different oxides scales depending on their chemical composition. For Ti0.30Al0.46Cr0.26N and Ti0.28Al0.34Cr0.42N, a Ti-O rich layer is formed on the top of a protective Al-Cr-O layer when the samples were tested at 900 ºC and 1000 ºC, being the oxide layers thicker for the higher temperature. Concerning the coating with the highest Cr content (Ti0.28Al0.31Cr0.51N), a compact and continuous Cr(Al)2O3 oxide layer was formed at 900 and 1000 ºC with residual TiO2 islands on the top, contributing for a significant enhancement of the oxidation resistance.

Resume : Though growth of indium gallium arsenide epitaxial layer on indium phosphide substrate is well reported, but for the micro-electronic application with the silicon based process technology, we need to transfer it to the Si substrate for monolithic integration circuits to fabricate high speed device. Moreover, Silicon substrate is less expensive and available with larger diameter than any other wafers. As, direct epitaxial layer growth of InGaAs is on Si substrate could not be achieved, other than low dimensional structures, a buffer layer of InP on Si can be introduced to get a lattice matched substrate. In our present investigation we tried to deposit InxGa1-xAs layer by Metal Organic Chemical Vapor Deposition (MOCVD) technique on Si substrate followed by an InP buffer layer. Indium gallium arsenide layer with indium phosphide buffer has been grown on p-type silicon (100) by Metal Organic Chemical Vapor Deposition (MOCVD) technique. The composition and the crystalline quality of the grown films have been investigated by UV-Vis-NIR reflectance spectroscopy and grazing incidence X-ray diffractometry (GIXRD). To get a lattice matched substrate an InP buffer layer is deposited onto Si substrate prior to InGaAs growth. The reflectance spectrum shows the band gap energy of the grown InGaAs layers are determined to be 0.82 eV and from the diffraction data the lattice constants of the grown layers are found to be 5.855 and 5.875 nm for two growth temperatures of 6000C and 650 0C for same precursors flow rates. Applying Vegard?s law, it is found that the results found from these two different techniques are consistent. The thickness and the growth rate are determined from the reflectance spectrum. It is found that the deposition lies in the mass transport limited regime for the mentioned temperature range.

Resume : Polycrystalline metallic films growing in a Volmer-Weber mode, as typically encountered during condensation of metal vapors on insulating substrates, are technologically important in a variety of applications, such as catalysis or plasmonics for which nanoparticle synthesis is a requisite. The nucleation, coalescence and continuous film growth stages of high-mobility metals are associated with a compressive-tensile-compressive behavior, as evidenced using real-time stress diagnostic. As the lateral grain size is usually set-in during the coalescence stage, controlling the nucleation conditions is of paramount importance for tuning the films properties as well as stress levels. This can be achieved by changing the substrate temperature or deposition flux. Here we employ Ge surfactant to vary the nucleation conditions during sputter-deposition of Cu films, and use a combination of in situ and real-time techniques to monitor the growth. We identify the percolation thickness from electrical resistivity measurements, while the onset of film continuity is determined from the maximum tensile force using a multiple beam optical stress sensor. Complementary analyses using atomic force and transmission electron microscopy are employed to obtain information on the growth morphology and grain size.

Resume : One of the key problems systems of electron and ion optics (mass spectrometers, ion trap, quadrupole systems, ion and electron transport systems) is a distortion of the electric field within the electrode system. The main cause of the distortion is the formation non-conductive polymeric hydrocarbon films on the electrodes surface, which are charged by the charged particle (ions and electrons) and causes significant distortion of electric field configuration. The traditional way to reduce the rate of formation of the films is continuous heating electrode system to 150-180 ° C, which results in high power consumption and causes additional distortions caused by thermal deformations. The paper presents a method of synthesis and characteristics of multilayered Indium-based functional coating provides effective removal of hydrocarbon-polymer film on electrodes surface. The self-cleaning physical principle consists in electrode system heating (periodic) to a temperature of 110-160 ° C causing melting Indium external layer of coating (about microns thickness). As a result of the melting of the external Indium layer of hydrocarbon-polymer film break and dissolve therein. The paper presents data on the optimal coating structure and thickness, at which the effective retention of the molten coating layer. The multilayer coating comprises an adhesion layer of copper and nickel barrier layer for increasing the number of effective absorption cycles. The paper presents the spatial distribution of elements on the coating thickness profile over time (after a few cycles). It was found that in the process of mutual diffusion of copper and indium. It is shown that the use of the Self-cleaning Indium-based functional coating results in a significant increase in the lifetime of devices electron and ion optics to 4-5 thousand hours. Experimental check has confirmed the advantages of the method of "self-cleaning" surfaces of the electrodes and, as a result, recovery of operating parameters of the mass spectrometer.

Resume : Skin-like, body attachable devices can be used in a variety of applications ranging from health monitoring systems and human-machine interfaces. They typically demand wireless capabilities to eliminate the physical bulk associated with power sources and obstacles associated with hard-wired connections to external data acquisition systems, respectively. Here, we report on a stretchable human motion monitoring system using GaInSn, a liquid phase eutectic metal alloy, with wireless capabilities using near-field-communication (NFC) technologies. Liquid metal traces were patterned on elastomer substrates via selective surface wetting of reduced GaInSn on a pre-patterned Au films. Complex patterns with resolution of 50 μm were achieved via this process. The liquid metal traces serve as a resistor-type strain sensor, electromagnetic antenna and electrical connections simultaneously in the integrated system. The fabricated strain sensor showed excellent durability for 10,000 stretching cycles under 30% strain, with a gauge factor of 2. Electrical and mechanical analysis of the sensor and inductive coil antenna including excremental measurements and theoretical simulations were performed for various deformations such as tensile (up to 30%) and compressive strains (up to 100 kPa). The demonstrations of motion monitoring include wrist flexion, movements of the vocal cord, and finger motions.

Resume : For reducing the risk of infections, the utilization of antimicrobial surfaces is mandatory. Methods for obtaining such surfaces are thoroughly investigated. Among possible approaches for obtaining antimicrobial surfaces are those based on cold atmospheric pressure plasmas. In this work we report on the deposition of silver-polymer nanocomposites by using an Atmospheric Pressure Discharge with Bare Electrodes (DBE) generated in argon. Ag nanoparticles admixed with HMDSO vapors are introduced in the remote discharge by means of an atomizer system working under continuous oxygen flow, leading to deposition of thin layers of silica-like matrix in which silver is embedded. Composition, chemical bonding and distribution of nanoparticles inside the nanocomposites were corelated to the experimental conditions as regarding the gaseous flows and precursors concentration. Surface morphology, topography and wettability characteristics were investigated in order to determine the optimal parameteres in respect to the desired surface properties. The potential of this method for obtaining highly efficient antibacterial surfaces at low cost is discussed. This work has been financed by the Romanian Ministry of Research and Innovation in the frame of Nucleus programme-contract 4N/2016 and PlasmaTex M-ERA-NET contract 31/2016.

Resume : In this work we have developed plasmonic Ag nanoparticles supported on Si substrates via a simple electroless deposition process eliminating the need of vacuum technology. The near- and far-field plasmonic performance of the produced nanoparticles were evaluated by surface-enhanced Raman scattering (using Rhodamine 6G as test molecule) and specular spectral reflectivity measurements, respectively. The factors influencing the development of nanoparticles, such as the type (p- or n-) and the orientation [100] or [111] of the substrate, the deposition time and the solution’s concentration were studied thoroughly by optical measurements, x-ray diffraction, auger electron spectroscopy and x-ray photoelectron spectroscopy. The deposition time, as well as the concentration, affected significantly the development and the growth rate of the particles making this technique an easy and inexpensive method for the development of tunable plasmonic nanoparticles. The produced plasmonic templates had improved signal-to-noise ratio by an order of magnitude for R6G compared to sputter-deposited Ag nanoparticles

Resume : Recently, considerable effort has focused on the functional coating of antibacterial properties in coated steel applications, and which seem to be quite useful in mobile devices, appliances, interior, buildings, and medical stuffs. For this, various bacteria-killing techniques have been developed, such as silver nanoparticles, layer-by-layer (LBL) nanofabrication, incorporation of various antibiotics, and so on. However, the antibacterial coating simultaneously keep up with other requirements like, anticorrosive, high gloss, suitable mechanical properties. In this work, we developed antibacterial coating formulation based on UV steel coating process by using chemically-modified urushiol lacquer. In fact, various kinds of lacquer trees (e.g., toxicodendron vernicifluum) have been used as paints and coating materials for woods and metal surfaces since 5,000 years in oriental culture. This natural lacquer exhibits superior barrier property against oxygen and water, as well as good durability, chemical resistance, and mechanical properties. However, traditional technique based on the enzymatic polymerization needs long time as well as manpower. In addition, pristine urushiol derivatives tend to inhibit free-radical polymerization due to its catechol structure of radical stabilization mechanism. Herein we present a facile method to minimize the radical inhibition for the development of antibacterial, anticorrosive, and high gloss UV coating formulation.

Resume : CrAlYN hard coatings with two different Al contents (16 and 25 at.%) and Y concentration varying between 1 and 5.7 at. % were deposited by direct current reactive magnetron sputtering on commercial M2 steel substrates by co-sputtering of Cr-Al mixed and Y targets. The samples were heated to 1000 ºC in air during 2 h to study their oxidation resistance and thermal stability. X-ray diffraction, glow-discharge optical emission spectroscopy and transmission electron microscopy coupled with spatially resolved microanalysis techniques were used to investigate the nanostructure, constituent phases and chemical elemental distribution of the as-prepared and oxidized samples. In previous work we reported that the Y acts as a reactive element, blocking the Fe and C diffusion from the substrate [1]. Here we show that the Y content is critical and depending on the Al content, different behavior is obtained. The highest oxidation resistance and best thermal stability is obtained for the CrAlN coating with 16 at.% Al and 2.9 at. % of Y content, where the initial nanostructure and the cubic phase (fcc-CrAlN) was retained, and a thin (Cr,Al)2O3 oxide protective scale was formed. At lower Y content (1.2 at.%) the iron diffused along the coating arriving to the surface where gets oxidized. Higher Y amount (4.6 at.%) avoided the iron diffusion but a thicker oxide scale is formed with new oxide phases, and the initial fcc-CrAlN phase is partially transformed to Cr7C3. The increment of Al content up to 25 at.% with Y concentration of 2.6 at.% presented a good oxidation resistance at 1000ºC but new phases (h-AlN and Cr-Fe) were formed. The coating with the same Al content but with higher amount of yttrium (5.7 at. %) is completely oxidized.

Resume : Self organization of colloidal particles has many applications, particularly in fabrication of solar cells with advanced light management strategies. We report a simple, facile spincoating based approach for fabricating two dimensional colloidal crystals with hexagonal and non hexagonal close packed (HCP) arrays with organic as well as inorganic colloidal particles on flat and nano patterned substrates, respectively. Appropriate amounts of surfactant molecules are added to the colloidal dispersion ahead of spin coating to ensure the formation of the HCP patterns. The non-HCP arrays are fabricated by spin coating the particles onto soft lithographically. The substrate patterns impose directionality to the particles by confining them within substrate grooves during spin coating, thereby breaking the hexagonal close packed symmetry into structures that are commensurative with the substrate patterns. Parameters like coating speed, dilution of the colloids, amount of surfactant added and volume dispensed provide a control over the formation of HCP as well as the number of layers deposited. We have also developed a novel technique by which the HCP as well as non-HCP array of the colloidal particles can be transferred to planar as well as non-planar surfaces. For this purpose the colloidal arrays are fabricated on a sacrificial PMMA layer which is subsequently degraded by UV exposure, resulting in transfer of the particles onto any other substrate, including non-planar, curves and rough surfaces. This allows the colloidal structures to be transported across substrates irrespective of their surface energy, wettability or morphology. Since the particle array is transferred onto a substrate, without exposing it to any kind of chemical or thermal environment, it can be utilized for placing particles on top of thin film solar cells for improving their absorption efficiency, without subjecting the completed cell to any further solution processing.

Resume : A systematic approach of using poly(oxyalkylene)-amine-salt terminated 2,2-bis(4-hydroxyphenyl)propane epoxy oligomers for modifying the layered silicate clays has led to the organoclays with different surfactant properties. The pristine layered structure of natural clays were organically intercalated into basal spacing from 12Å to 100Å and even exfoliated to form randomized thin layer silicate platelets by the amine-oligomers as the first step. These organoclays were characterized by X-ray diffraction and shown their expanded basal spacing up to 100 Å and even randomized into featureless, confirmed by TEM examination. Furthermore, the removal of the amine-oligomers left the hydrophilic randomized thin layer silicate platelets in water phase in the second step. The balance of organic amine-oligomers and inorganic silicate platelets in the structure led to the amphiphilic property. The amphiphilic nature was evidenced by their ability of lowering the surface tension at the water–air interface. The platelet ionic charges were analyzed by zeta potential measurement showing a pH-dependent charge species existed on the surface of the random platelets and the demonstration of charge reverse properties depending on pH. The extremely stable emulsions can be formed for the clay–amine suspension, suggesting the practical uses for pigment dispersion in coating applications.

Resume : This study aimed to design hybrid structures based on green nanosilver, bio-polysaccharides, and biomimetic membranes, by using a “green” bottom-up approach. Living plant material was employed to prepare silver nanoparticles. Chlorophyll a embedded in the artificial lipid bilayers was used as optical sensor to monitor the formation of biohybrids. Modern biophysical methods (UV-Vis absorption and emission spectroscopy, AFM, DLS, zeta potential measurements, antioxidant and antimicrobial assays) were used to characterize these bio-based nanocomposites. The obtained biohybrids exhibited high antioxidant activity (checked by chemiluminescence method), and also strong biocidal properties against E.coli, E. faecalis and S. aureus, thus they could be used in biomedical applications as protective biocompatible coatings.

Resume : Surface acoustic wave (SAW) devices has been the most suitable platform for the fabrication of any kind of sensor in the last decade. Device properties including cost effectiveness, small size, high sensitivity and wireless detection are grabbing the attention of the researchers towards the realization of SAW sensors. Commercial SAW devices are being exploited successfully for sensing harmful radiations, toxic gases and biological analytes after integration with suitable sensing layer. Since NO2 is toxic gas and is emitted continuously from vehicles and factories, it needs to be monitored continuously. There are few reports in the literature showing NO2 gas sensor based on commercial SAW filters, but with low sensitivity. In order to improve the sensitivity, SAW resonator could be exploited where acoustic energy is confined yielding low losses. The present work reports the fabrication details of 100 MHz SAW resonator based on ST cut Quartz. Reflectors are placed on both sides of interdigital transducers to confine the acoustic energy on the device surface by forming standing waves. Subsequently PZT thin film has been deposited by pulsed laser deposition as a sensing layer over the fabricated SAW resonator. Shift in resonator frequency was measured precisely for varying concentration of NOx gas. The calibration curve was found to be linear which is advantageous for integrating with electronic circuitry for handheld wireless sensing device.

Resume : Carbon monoxide (CO) is a colourless, odourless and tasteless gas and is known as silent killer because of its highly toxic nature. It enters into the bloodstream and combines with haemoglobin to form carboxyhaemoglobin, which makes the blood unable to carry oxygen that destroys the human body?s cells and tissues. Thus, there is an urgent need of highly sensitive and selective sensor for the detection of CO gas. Gas sensing phenomenon is strongly influenced by the surface area and morphology of the sensing layer. In this context, nanostructured Zinc Oxide (ZnO) thin film is the best suited material for detection of harmful gases. In the present work, ZnO thin film has been grown by rf sputtering technique in glancing angle deposition (GLAD) configuration. This sensing layer has been deposited on Pt inter digital electrodes (IDEs) patterned glass substrates using a metal Zn target in a mixer of Ar and O2 (1:1) gas ambient. X-Ray diffraction study reveals that the sensing films are highly c-axis oriented and having well defined reflection corresponding to (002) plane of ZnO. The AFM image confirms the formation of highly porous and columnar structures. ZnO nanostructures grown at a GLAD angle of 70° exhibit sensing response of about 372 at a relatively lower operating temperature of 130?C toward 500 ppm of CO gas. The sensor is found to exhibit fast response (46s) and recovery (359s) speeds with high selectivity towards detection of CO.

Resume : Diamond-like carbon thin films (DLC) can develop properties such as ultra-low friction coefficient and low wear rates. One of the biggest problems of this coating is its poor adhesion in some substrates, such as low-alloys steels. Many efforts are devoted to study alternatives in order to overcome this problem, like different chemical architectures of interlayers. However, the use of silicon-containing interlayers demands high deposition temperatures, which might degrade previous heat treatments . The aim of this work is to investigate an alternative pre-treatment to reach high enough adhesion in low temperature. A hydrogen plasma etching was used at different times and temperatures to perform a selective chemical cleaning of the silicon-containing interlayer, prior to DLC deposition. The samples were produced by EC-PECVD and characterized by SEM, GDOES and adhesion tests. The chemical structure of the interlayer shows a higher content of carbon atoms in the interface, which is a known factor to improve adhesion, at longer times than 4 min. The produced chemical architecture promotes good adhesion of the DLC temperatures as lower temperatures as 85°C when previous works have only reported good results in temperatures up to 300°C. We propose a mechanism to explain the hydrogen etching and analyze the new pathways generated by this work.

Resume : A triboelectric nanogenerator (TENG), a renewable energy technology to efficiently harvest mechanical energy into electrical energy, has elicited worldwide attention because of its cost-effectiveness and sustainability. This device utilizes contact electrification which is induced by friction between two dielectrics with triboelectric polarity to produce electricity from wasted mechanical energy. Recently, the TENG was developed using water-solid contact electrification, which used water as dielectric itself and significantly reduced the friction damage between two materials. In this study, we developed a cylindrical water triboelectric nanogenerator which controls the water flow by fabricating patterned hydrophobic/-philic surface with polytetrafluoroethylene (PTFE) nanocoated surface and anodized aluminum oxide nanopores. As a first report, this study demonstrates new design of fully packaged water-solid contact TENG, called cylindrical water triboelectric nanogenerator (CW-TENG), which has a complete packaged design to generate multiple output in single rotation through patterned surface. CW-TENG can be integrated with multiple generating hydrophobic/-philic generating units in single TENG device without occupying extra space for installation. Furthermore, this study is the first to demonstrate possibility of using hydrophilic surface as additional energy harvesting device as well as water reservoir in a packaged design. Until now, hydrophilic surface was only considered as incompatible element for TENG because water volume on the hydrophilic surface remains after the first contact. The rotating design pushes water on the hydrophilic surface constantly to force the water volume change to induce electrical potential difference between two surfaces. In addition, this study demonstrates analysis of the electrical energy generation by water volume change on the hydrophilic surface with computational dynamic simulation. The electrical potential difference between water and the electrode is shown to increase as the water volume change is increased. Utilizing this new result and analysis, various TENG design using hydrophilic surface can be developed for practical use. In this design, the super-hydrophobic surface TENG generates open-circuit voltage (VOC) of 7 V and closed circuit current (ICC) of 50 nA, and hydrophilic surface TENG can produce VOC of 2 V and ICC of 60 nA. With more super-hydrophobic and hydrophilic patterned electrode inside this device, the total power generated by the device is estimated to be multiplied. Thus, with this research will provide a potential solution of energy harvesting using water flow and self-powered system.

Resume : The catecholamines such as dopamine, norepinephrine, and epinephrine are the principal neurotransmitters in the sympathetic nervous system. Catecholamines and their metabolites are considered to be important markers of socially significant diseases such as atherosclerosis, diabetes, coronary heart disease, carcinogenesis, Alzheimer's and Parkinson's diseases. Currently, neurotransmitters can be studied via electrochemical and chromatographic techniques that provide characterization and quantification, although these techniques can only provide crude spatial information. Besides, the difficulty of catecholamine determination in biological materials is associated with their low normal concentrations (about 1 nM) in biomaterials, which may become even one more order lower because of some disorders. In addition, in blood they are rapidly oxidized by monoaminooxidases from thrombocytes and, for this reason, the determination of neurotransmitter metabolism indicators in organism should be very rapid (15?30 min), especially in critical states. Unfortunately, modern instrumental analysis does not offer a complex solution of this problem: despite its high sensitivity and selectivity, HPLC-MS cannot provide sufficiently rapid analysis, while enzymatic biosensors and immunoassays for the determination of the considered analytes lack sufficient sensitivity and reproducibility. Fluorescent and SERS-sensors remain a compelling technology for approaching the general problem of selective neurotransmitter detection. In recent years, a number of catecholamine sensors have been reported including RNA aptamers, fluorescent ribonucleopeptide (RNP) complexes, and boronic acid based synthetic receptors and the sensor operated in a turn-off mode. In this work we present the fluorescent and SERS turn-on sensor systems based on the bio- or chemorecognizing nanostructured films {chitosan-Tb/Eu/Cu-nanoparticles-indicator reagents} that allows for the selective recognition, visualization and sensing of the above mentioned catecholamines on the level of nanomolar concentration in biomaterials (cell cultures, tissue etc.). It was (1) developed optically transparent porous films and gels of chitosan; (2) ensured functionalization of the surface by molecules-«recognizers» (by impregnation and immobilization of components of the indicator systems: biorecognizing and auxiliary reagents); (3) performed computer simulation for theoretical prediction and interpretation of some properties of the developed materials and obtained analytical signals in biomaterials. We are grateful for the financial support of this research from Russian Foundation for Basic Research (grants no. 15-03-05064 a, and 15-29-01330 ofi_m).

Resume : Patterning of functional nanomaterials on surfaces at nanometer length scales are critically important to many applications and scientific fields. Here we show far field (ES) and near field electrospinning (NFES) techniques can be used for generating patterns of polymer brush nanoribbons (PBNR) as small as 100 nm on surfaces as a low-cost simple process as called by us Electrospin Nanolitography (ESPNL). In this study we demonstrate two unique approaches to fabricate PBNRs aid of electrospun nanofibers. At first approach, polymers which can be graft as polymer brushes on surfaces are directly electrospun on surface. Polymer fibers on the surface through thermal annealing followed by washing leads patterns of PBNRs. At second and more effective approach, we use electrospun nanofibers masks on top of a substrate grafted polymer brushes. The oxygen plasma etching and washing of the substrate leads to patterns of PBNRs. PBNR arrays can be aligned by rotating drum collector. Furthermore desired geometric patterns of PBNRs were fabricated easily by using NFES technique. These alignment or geometrically designed patterns then be used to selectively localize nanomaterials such gold and silver nanoparticles. Results of our study show that the width of the PBNRs can be controlled with the fiber as well as ES and NFES conditions. We fabricated patterned PBNRs with less than 50 nm. To demonstrate an example of possible application of this technique, Au NPs with different size and shape were selectively immobilized on PBNRs to generate heterostructures. These structures performed strong surface enhance Raman scattering effect (SERS) for plasmonic and signal sensing applications. Also patterned Au nanoribbons with different size and shape can also use as nano cables for electronic industry. To sum, the scalability and simplicity of ESPNL hold great promise in patterning of a broad range of functional nanomaterials for different application related nanolithography techniques. With our technique not only PBNRs and also functional materials such as graphene, polydopamine or coated thin films can be fabricated and also patterned in desired shape with high resolution as small as 100 nm easily. Also as we shown functional nanoparticles can be selectively immobolize on these nano ribbons for wide range of applications.

Resume : Nanomedicine provides a new paradigm of rational delivery of therapeutic and diagnostic agents to the diseased sites that renders site specific therapy. In the case of atherosclerosis, the detection of vulnerable plaques that are prone to rupture is a challenge that needs to be addressed for the reduction of incidence of heart attack and stroke in younger patients. This talk focuses on Nanomedical targeting strategies in atherosclerosis and possible molecular targets within the plaque to regress its progression. An overview of the diversity of the nanoparticulate systems with surface ligands targeted for macrophages and other cell types of the vulnerable plaques will be given in line with drug delivery systems that elicit anti-inflammatory/- proliferative drugs. The Bioelectronics strategy encompasses the application of conductive polymers and devices that due to their high ionic and electronic conductivity can merge as translators between the ‘nanoworld’ of the cells with the implant interface. Tissue regeneration activities are essential for dealing with the late stent thrombosis of drug eluting stents (DES) that it is mainly caused by delayed endothelialisation. The new perspectives of organic bioelectronics and their marriage with nanomedicine aimed for atherosclerosis will be highlighted providing intelligent solutions for its accurate diagnosis and effective therapy. Acknowledgements This work has been supported by the EU FP7-REGPOT 2011-1 Project ROleMak, GA 2860 an

Resume : Over the last decades a lot of attention was devoted to Ni-Mn-In Heusler alloys, because of their intriguing properties important for various applications, such as caloric effects, theoretically predicted high spin polarization, magnetic-induced first-order phase transition etc. Many of these properties originate from the martensitic transition. Due to the possibility of using this effects for different applications a lot of scientific and technological attention is attracted now to the low-dimensional materials like thin films. Therefore, it's very important to determine structural and magnetic properties changing upon the decreasing z-dimension of the material from bulk to few atomic layers film. Martensitic transition is a first-order reversal structural transition from high temperature cubic phase to martensitic phase with lower symmetry. In this work the polycrystalline Heusler alloy thin films with Ni52Mn48-xInx (12< x< 16) composition and thicknesses about 50 nm were grown by pulsed laser deposition. The magnetic attributes of martensitic transition, observed by PPMS, were found in a much wider temperature interval (about 200 K), than structural ones, studied by X-ray diffraction (about 90 K only). The similar broader temperature range of transition is observed for electronic structure investigation of the valence band, provided by hard X-ray photoelectron spectroscopy on P09 beamline at PETRA III synchrotron source. The thermomagnetic investigations are concluded as more accurate approach for martensitic transition characterization for thin films.

Resume : Quantum dots (QDs) have been used increasingly to achieve broader color gamut and enhance power efficiency in displays due to their narrow emission band and high photoluminescence quantum yield (PLQY). The most common application form of QDs in display nowadays is to incorporate QDs in a polymer film that used as a luminescent down-shifting layer in liquid crystal displays (LCDs). In this study, we fabricate uniform QD/polymer with a high light-conversion efficiency (LCE). We have achieved good QD dispersion in the polymer to retain its high PLQY and improve the stability. We have also investigated the effects of scatter particles (SCs) with different sizes on the optical properties and efficiency of the QD/polymer films. We found that the scattered light from the film increases with the increasing of SCs amount in the polymer matrix; whereas the LCE of the film drops after reaching a certain SCs concentration in the matrix due to the saturation of the light path.

Resume : All-solid-state thin-film lithium ion batteries have a great application potential, in particular for the use in microsystem technologies, such as MEMS, CMOS memories, medical implants and devices, smart cards, skin patch, RFID, wearables, E-textiles, smart phones, due to their high power density and high safety. All-solid-state lithium ion batteries comprise three main parts, the cathode, solid state electrolyte, and anode, in addition to two art collectors for the cathode and anode, respectively. Besides the material properties of individual components, the contact of the current collectors to the anode and cathode, as well as the interfaces between the cathode, anode and solid state electrolyte are of crucial importance for the battery performance. This article provides an overview of the current research status, highlighting the individual battery components in terms of their material selection, constitution, microstructure as well as the physical, chemical and electrical properties. Important analysis techniques, particularly in-situ analysis, and simulation methods are exemplarily presented. The challenges in up-scaling, deposition on flexible substrates such as metal sheets, polymer substrates and ultrathin glasses and the possibility of the realization of a roll to roll process will also be discussed.

Resume : Hydrogenated amorphous silicon material has been investigated extensively for its application in thin film solar cells. However, defects, stability and reproducibility are few of the important issues for its large scale application in commercial devices. A combinatorial effect of the parameters like optical absorption, photo-electric sensitivity, carrier mobility-lifetime product, optical gap, atomic structure of the material, defect density etc also is thought to limit the maximum achievable device efficiency. We investigated effect of a pair of complementary material parameters to determine maximum achievable device efficiency. In this regard defect density and thickness of active layer were found to form a complementary pair with which a maximum device efficiency is achievable. In our investigation, the defect densities of solar cell active layers were in the range of 4×1015 to 8×1017 cm-3, and its thickness were in the range of 25 to 3000nm. We observed that the highest available device efficiency (Eff) of the solar cells and defect density (Ndd) of the active layers are related by Eff =0.544 –0.0278 Log10(Ndd). For example, a solar cell with 10% efficiency can be obtained if defect density of active layer, Ndd = 8.9×1015 cm-3 whereas a 20% efficient solar cell can be obtained if the Ndd = 1.0×1012 cm-3.

Resume : This paper reports a study over a wide range of high-K dielectric materials deposited by different techniques for high power RF MEMS switches applications. For capacitive switches, dielectric material optimization is one solution to further increase power handling and reliability alongside design improvement. For electrostatic MEMS switches under high RF power (>20W), the dielectric material has to withstand high electric field (>4MV/cm). Through dielectric study, we intend to introduce promising materials in order to go beyond demonstrated power handling of 20W with reliability up to 10^7 cycles [1]-[2]. E-beam evaporation with Ion Assisted Deposition and Atomic Layer Deposition were studied based on three High k materials : Al2O3, HfO2 and TiO2. These materials were compared to Si3N4 Plasma Enhanced Chemical Vapor Deposition, as reference material. Crossed electrical characterizations on MIM capacitors and physical analyses were performed on all materials. This study shows that electrical properties of ALD materials are in good agreement with Mc Pherson & Al. trend [3] regardless of allowed oxygen excess and carbon contamination. This means that high-K materials can be tuned using ALD depending on application specifications. ALD HfO2 insulators were identified as promising for high power RF applications. Preliminary tests to integrate thermal ALD HfO2 in RF MEMS switches show that it is possible to further enhance DC stress handling without RF performance degradation. References [1] H.-H. Yang, H. Zareie, G. M. Rebeiz, Journal of Microelectromechanical Systems 24, 599 – 607 (2015) [2] A. Ziaei, S. Bansropun, P. Martins, M. Le Baillif, European Solid State Device Research Conference 2015 (ESSDERC), 153 (2015) [3] J. Mc Pherson and Al., Appl. Phys. Lett. 82, 2121 (2003).

Resume : Coating non-planar microstructured surfaces is highly challenging, especially when a high degree of conformality is required. Typically, such conformal coatings are championed by atomic layer deposition (ALD). However, ALD struggles to reach a thickness of several tens of nanometers, because of the long deposition times. Here, we present ultrasonic spraycoating of solution precursors, which achieved uniform coatings on structures with aspect ratio 10. Since such precursors can be synthesized for most metal ions, a wide range of materials is accessible. Here, we focused on anodes (TiO2, LTO, WO3), cathodes (LMO), solid electrolytes (LLT), as well as current collectors (ITO) for the fabrication of a 3D thin film lithium ion battery. Insights into the spraycoating process and the precursor chemistry explained the success of the method. The properties of the individual battery components (crystal structure, morphology, CV curves, charge-discharge profiles,…) and the specific material’s integration issues will be discussed. The capacity enhancement finally reached a factor 4. This remains unrivaled at the moment, also for vacuum based deposition methods such as CVD. IWT project SBO SOSLION and UHasselt (BOF-IOF) are acknowledged for financial support. E. J. van den Ham, et al. ACS ENERGY LETTERS, 2016 1, p.1184-1188 G. Maino, et al. J. Mater. Chem. A, 2016, 4, p. 18457-18469 E. J. Van Den Ham, et al. RSC Advances 2016, 6, p. 51747-51756

Resume : Solar photo thermal conversion of photovoltaic devices at elevated temperatures can be enhanced by exploitation of thermally stable spectrally selective coatings. One of the critical approaches is designing nanocermet layers as a part of a multilayer stack with a stable dielectric matrix and encapsulated metallic nanoparticles with low thermal diffusion. In our study, ultrastable TiAlN and AlN semiconducting compounds were synthesised by magnetron sputtering for high temperature solar thermal applications. It is believed that transported fractions of transitional metal into a dielectric AlN matrix can stabilize a newly formed TiAlN alloy and boost thermal tolerance. The dynamic in-situ X-Ray diffraction studies show that single layers of TiAlN and AlN on a tantalum substrate can tolerate the temperature annealing up too 1400K in vacuum ambient with no structural change. No oxidation or interdiffusion reaction with the substrate was observed. High resolution transmission electron microscopy (HRTEM) analysis was conducted to understand the microstructural nature of a solid TiAlN solution with a face centred cubic (FCC) structure. Optical modelling using WVASE software (J.A. Woollam Co.) and experimentally determined optical constants of the deposited thin films demonstrates that a TiAlN/AlN based multilayer is a great candidate for solar selective absorption, with an integrated solar absorption ranging between 90% and 97%. This implies the potential use of superior thermally stable TiAlN/AlN based spectrally selective multilayer coatings to achieve higher efficiency in thermo-photovoltaic devices.

Resume : The reliability of electronic components is affected by dielectric layer aging. When component sizes are reduced insulator films are subject to high applied electric fields (MV/cm) and charges can be injected. These charges modify component properties and can lead to system failure. A better dielectric charging understanding enables charge accumulation control. In this work dielectric charging process in capacitive structures under bias voltage is investigated. We particularly focus on the case of capacitors with silicon nitride dielectric thin layers. A one dimensional dielectric charging model is presented including free and trapped carrier transport. This is based on the resolution of both Maxwell-Gauss and charge continuity equations. Several relevant charge transport mechanisms are taken into account. Trap Assisted Tunneling effect and Schottky injection are the interfacial mechanisms, trapping and detrapping mechanisms (including Frenkel-Poole effect) and space charge limited current are considered for bulk mechanisms. Electric field, current and charge carrier distribution can be calculated in the whole dielectric layer as a function of time. Simulated currents show the same order of magnitude as measured currents for different applied electric fields. Adding the discharging process, this model becomes a forecasting tool for component lifetime. The proposed model can be used as a simulation tool to choose materials according to device performances targeted.

Resume : Nanomaterials are a topic of increased interest for many applications. Reactive Al/Ni multi-layer thin film can produce rapid bursts of heat and light through a homogeneous or self-propagating reaction. The exothermic reactions can be ignited using pulses of electrical, mechanical, optical, or thermal energy. In this paper, Al/Ni nano multi-layer thin film was fabricated using magnetron sputter deposition. Transmission Electron Microscope(TEM) was used to characterize the section configuration of the thin film. Then, taking advantage of standard photolithography and developing technology, a type thin film high voltage switch was fabricated. The switch was composed by two main electrodes and a trigger electrode, and paraxylene film was used as insulating medium between main electrodes. Scanning electron microscope (SEM) and stylus profiler was employed to ascertain multi-layer structure and dimension of the switch. Then, we discussed the discharge characterization of the Al/Ni thin film switch using electrical and laser energy as a trigger method. We carefully examined the delay time, the peak current of the discharge circuit under different charging voltage and different trigger method. The switches in our work were connected to a capacitive discharge circuit and tested, and a 0.22 µF capacitor was charged to a certain volts. One pulse trigger voltage which was applied between trigger electrode and ground of the circuit was employed to initiate the actuation of the switch. DPO3054 oscillograph and a Rogowski coil current transformer were utilized to monitor the current waveform of the circuit. Compared with commercial stereo spark gap switch, because the energetic thin film was utilized to cause the break-over of the high voltage switch. The switch could be triggered by a voltage as low as 50V, which obviously could reduce the volume of trigger circuit. When the thin film high voltage switch was connected into a capacitive discharge unit(CDU), the discharge circuit had lower inductance and higher resistance. Using laser trigger method, the current-carrying ability of the switch was enhanced. The peak current is about 2700 A when the charging voltage is 2500 V. In order to understand discharge process further, the high-speed photography (HSP) technique and spectral temperature measurement technology were applied to the investigation of discharge process of the witch. Ablation of the electrodes was analyzed using metallographic microscope.

Resume : Plasmonic nanostructures have been proposed as potential materials for the development of biochemical sensors and surface-enhanced spectroscopies. Noble metals nanostructures have been generally used for surface plasmon technology in the visible, however they present limitations for longer wavelength applications. Highly doped semiconductors (HDSC) have been recently proposed as potential materials for the development of sensing devices in the mid-IR, molecule fingerprint region. In particular, the system based on 1-dimensional (1-D) Si-doped InAsSb/GaSb nano-antennas have proved to outperform gold standards in this spectral range and demonstrated surface plasmon resonance (SPR) sensing. SPR and surface enhanced infrared absorption (SEIRA) are compatible techniques for sensing in the mid-IR. Their combination enables the accurate identification of surrounding molecules. In this work, we demonstrate SEIRA sensing of 1-D Si:InAsSb/GaSb nano-antennas devices by using a SiO2 layer. The nano-antennas were designed to have a LSPR peak at the energy to reach the maximum electric field exaltation. Different SiO2 thickness were deposited on top of the nanostructures by e-beam physical evaporation. We report a clear dependence of the SEIRA sensing on the thickness of the SiO2 and the control of the nano-antennas fabrication to obtain the maximum enhancement of the molecule IR absorption, and thus to improve the sensing device efficiency.

Resume : Transparent conducting oxides (TCO), acting as transparent electrodes, are essential components in the basic structure of a large number of electronic devices as flat panel displays, touch screens, photovoltaic cells, lighting emitting diodes or electrochromic systems. The trade-off between transparency and conductivity in these materials is a major bottleneck towards higher device performance. Indium tin oxide (ITO) is the most established transparent conductive film in the market as currently presents the best optoelectronic properties. The current solution to further improve conductive properties of these materials is to deposit some metallic grids or nanowires on surface of the TCOs but transparency is always decreased and different manufacturing processes are combined. In this work, Ag nanoparticles deposited by gas aggregation sources has been incorporated into ITO layers deposited by DC pulse magnetron sputtering improving the conductivity of the layers while keeping transmission values by a simple one step process. The study of the composite optoelectronic properties has been carried out as a function of the process parameters to correlate those properties with the composition and morphology of the layers. The influence of the nanoparticles density has been carried out to optimise optoelectronic properties. This hybrid electrode is demonstrated to have a 5 times smaller sheet resistance compare to a single TCO layer, while maintaining high light transmission in a wide wavelength range.

Resume : Ag-ZrO2 cermet coatings on aluminized steel sheet have been obtained by a step by step approach to a multilayer system using uniquely the chemical spray pyrolysis technique. First single layers of metallic silver particles and zirconia were prepared on aluminized steel sheet (AS) and spray parameters were optimized. Then cermet coatings with different layers (ZrO2/Ag/AS; ZrO2/Ag ZrO2/AS; ZrO2/Ag ZrO2/Ag/ZrO2/AS) were prepared and studied with respect to their functional application for solar thermal devices. As evidenced by SEM and AFM studies, silver nanoparticles with a size distribution of 10 to 50 nm imbedded in zirconia can be obtained with a simple air pressure spray technique. Solar parameters as solar absorptance (AM 1.5) and thermal emittance (373K) were determined showing to reach 90% and 20% respectively. Layer thicknesses and chemical compositions were investigated with C60 XPS depth profiling showing small amounts of silver at the top most surface of the coatings and silver particle size distributions in agreement to the observations made by SEM/AFM. The stability of the coating system was evaluated for harsh environment with cyclic voltammetry and amperometry and outdoor exposure measurements.

Resume : Amorphous silicon carbonitride (SiCN) thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) from a pure Si target in argon/nitrogen/acetylene plasmas. The influence of the acetylene flow (0-50 sccm), substrate temperature (no additional heating-510 °C), HiPIMS pulse frequency (200-1200 Hz at an average target power of 1200 W), and negative substrate bias (60-200 V) on the resulting film properties were investigated. For all processes, the nitrogen-to-argon flow ratio was set to 0.28 at a pressure of 400 mPa, while the pressure was let to increase as acetylene was introduced into the chamber. X-ray photoelectron spectroscopy shows an increasing film carbon content from ~9 at.% to ~90 at.% as the acetylene flow is increased from 2 sccm to 50 sccm. Simultaneously, the film density decreases from ~3.0 g/cm3 to ~1.6 g/cm3. For films with C contents ≤20 at.%, hardness values between 21 and 22 GPa were measured by nanoindentation, resembling a similar hardness as the SiN reference sample. These films show dense and featureless morphologies when viewed in cross-sectional scanning electron microscopy. As the C contents increase, an increasingly columnar morphology is observed and the hardness values decrease to a minimum of ~5 GPa. The results indicate that low acetylene flows can be used as the C-source for SiCN films deposited by HiPIMS, while not compromising the desirable mechanical properties of SiN.

Resume : Free electron lasers (FELs) are the 4th generation of light source for the study of structural and time resolved properties of material and molecular. FELs are a pulsed, coherent, tuneable and monochromatic light source that works from THz to X-rays in time scales of fs and six order of magnitude brighter than the 3rd generation of light source such as synchrotron. In FELs, the quality of the emitted radiation depends on the quality of the electron beam as they are a single pass device. Therefore, the improvement on the design and efficiency of the photocathode as the source of electrons are a key factor. However, the emission mechanism and how this depends on the material properties is not clear. In this work, an approach to the photoemission of electrons is studied with ab initio calculations and an extension of Spicer’s three steps model. This approach is able to correlate directly the photoemission to the electronic, atomic and chemical structure of the surface. Surface engineering of photocathodes show promising possibilities in the control of their properties. It has previously been demonstrated that thin metal oxide films can generate surface localised states and alter the workfunction of the surface. A systematic understanding of these interactions is therefore a promising approach to engineering highly efficient photocathodes. Our approach, suggest that metal thin oxide over metal photocathodes can be used to increase the quantum efficiency of materials.

Resume : The elaboration and deposition effect of silver nanoparticles on optical and electrical properties of porous silicon layer was investigated. The silver nanoparticles were deposited on porous silicon layer using a thermal evaporation method followed by a thermal treatment at 180°C under nitrogen atmosphere. Photoluminescence and UV_Visible analysis of the treated samples were examined to understand the role of silver nanoparticles. The effect of the deposited nanoparticles on the electrical properties was evaluated by the AC impedance spectroscopy. The results indicate that the formation of the metal nanoparticles is accompanied by enhanced photoluminescence intensity and improved electrical parameters.

Resume : Capillary bridge formation between adjacent surfaces in humid environments is a ubiquitous phenomenon. It strongly influences tribological performance with respect to adhesion, friction and wear. Only a few studies, however, assess capillary dynamics. Here we focus on how capillary nucleation influences adhesion energy dynamically. Microcantilevers adhered to the adjacent surface are used to measure adhesion energy. Our experimental results indicate a logarithmic decrease in average crack healing velocity as energy release rate increases. Our goal is to model those results. We assume that capillary dynamics involve two mechanisms during the evolving of the capillary force: capillary nucleation and capillary growth. We find that by incorporating interface roughness details and the presence of an adsorbed water layer, the behavior of capillary force dynamics can be understood quantitatively. To fully capture the results, however, the theoretical model for nucleation time required an empirical modification. Our model enables significant insight into capillary bridge dynamics, with a goal of attaining a predictive capability for this important microelectromechanical systems (MEMS) reliability failure mechanism.

Resume : Vanadium pentoxide or vanadia (V2O5) is one of the few oxides having versatile redox dependent properties due to the multiple valence state of vanadium and as a result it can be used in numerous applications, such as catalysis, electrochromism and gas sensing. Furthermore, vanadium dioxide (VO2), is a well known thermochromic material, since it undergoes a semiconductor to metal transition (SMT) at a critical transition temperature TC = 68 oC that is close to room temperature. In this work, solution based Vanadium oxides (V2O5 and VO2) nanostructured thin films have been developed by aerosol spray pyrolysis and were deposited on Corning glass substrates. The structure of the films was characterized by X-Ray diffraction (XRD) technique, while Atomic Force Microscopy (AFM) was employed for surface analysis of the films. V2O5 films were tested against ozone showing a change of electrical current of about 1 order of magnitude at 5 ppb ozone concentration. Finaly, V2O5 films were post-annealed in order to take thermochromic VO2 phase. A decrease of IR transmittance of more than 3% at λ = 2500 nm, upon heating.

Resume : The aim of this work is to investigate the influence of Rh6G concentration on optical and thermal properties of nanocomposite porous silicon-Rh6G. Photothermal spectroscopy is carried out in order to determine optical spectra and gap energy of nanocomposite samples which is found to increase with Rh6G concentrations. Photothermal deflection is used to measure nanocomposite thermal conductivity. Nanocomposite thermal conduction is enhanced by the insertion of Rhodamine molecules in the porous matrix. Also, Photoluminescence spectra show an enhancement of energy transfer from porous silicon to nanocomposite band due to Rh6G.

Resume : Single-layer graphene (SLG), as transmission electron microscope (TEM) sample support, offers enormous potential to image nanoparticle, single molecule and ad-atoms at atomic resolution - [1]. Available experimental evidence involving the adsorption mechanism of individual molecules on pristine free-standing SLG is scarce and the resolution of TEM micrograph is limited by low signal to noise ratio. Here, we show that phosphotungstic acid (PTA) molecules have greater affinity to adsorb onto amorphous impurity present on graphene compared to pristine SLG. Furthermore, atomic-scale characterization of the PTA molecule [PW12O40]3- adsorbed on SLG using low-voltage (80 keV) aberration-corrected, high-resolution TEM was performed. This work demonstrates how electrospray ion-beam deposition (ES-IBD) - [2] can be effectively used to land molecules onto ultra-clean SLG - [3] using different landing energies in ultra-high vacuum (UHV) condition. Our study provides first experimental results involving soft landing, adsorption and characterization of individual poly-oxo-metalate (POM) anions onto SLG which can give insight into fabrication of complex two-dimensional materials involving graphene and POM molecules that could find application in electrochemistry and catalysis - [4]. References [1] Nair, R. R. et al., Applied Physics Letters, 97(15), 153102, (2010) [2] Rauschenbach, S. et al., Small, 2, 540-547, (2006) [3] Longchamp, J-N. et al., Journal of Vacuum Science & Technology, B 31, 020605, (2013) [4] Mizuno, Noritaka et al., Chemical Reviews, 98.1, 199-218, (1998)

Resume : The advanced materials process utilizing non-thermal plasmas with a high plasma density enables the synthesis of small-to-big sized Si quantum dots (QDs) by combining low-temperature deposition with superior crystalline quality in the background of an amorphous hydrogenated silicon nitride matrix. The characterization of plasma and atomic radical parameters along with the energy influx from plasma to the substrate during plasma enhanced chemical vapor deposition (PECVD) of Si QD films is presented and discussed. Particularly, relating to the Si QD process optimization and control of film growth, the necessity to control the deposition environment by inducing the effect of the energy of the key plasma species is realized. In this work, we report dual frequency PECVD processes for the low-temperature and high-rate deposition of Si QDs by chemistry and energy control of the key plasma species. The dual frequency plasmas can effectively produce a very high plasma density and atomic H and N densities, which are found to be crucial for the growth and nucleation of QDs. Apart from the study of plasma chemistry, the crucial role of the energy imparted due to these plasma activated species on the substrate is determined in light of QD formation. Various plasma diagnostics and film analysis methods are integrated to correlate the effect of plasma and energy flux on the properties of the deposited films prepared in the reactive mixtures of SiH4/NH3 at various pressures. The analysis reveals that the plasma chemistry plays a crucial role in shaping the QD size with an overall variation from ~ 4 to 11 nm in an amorphous silicon nitride network for the films deposited at various pressures. The present results are highly relevant to the development of the next-generation plasma process for devices that rely on effective control of the QD size and film properties.

Resume : The coating industry has been working to improve surface properties targeting an improvement of corrosion and wear resistances, adhesion, among others. In many cases, nanocoating acting as protective films may prevent future problems and extend the devices lifetime. In this sense, polymer nanocomposites have recently attracted major attention because the synthesis process is cheap and the process to apply on steel substrates is easy. The graphene oxide combined with polymers were revealed an impermeable nanocomposite to gases and liquids and from this perspective have attracted particular interest to application on oil and gas industries. In this work, we report the methodology to produce the nanocomposite film of polyurethane and graphene oxide (GO), as well as reduced graphene oxide (RGO), applied on steel stainless (X80 API 5L). The samples were characterized by optical and scanning electron microscopy (SEM), XPS, Raman Spectroscopy, nanoscratch tests for adhesion behaviour. The dispersion of GO and RGO throughout the composite is also discussed. Corrosion tests reveal that the use of RGO increases the corrosion resistance. 
This work is partially supported by University of Birmingham and by the Brazilian agencies: CNPq and FAPERJ

Resume : The build-up of residual stresses in physical vapour deposited hard coatings can lead to delamination and crack formation when a critical stress value is exceeded. This limits the maximum possible coating thickness. For some applications, however, thick coatings are desired as they often possess superior properties in comparison with their thinner counterparts. It is therefore of uttermost importance to understand, how residual stresses build up and how the stress state can be tailored. In this contribution, we systematically studied the residual stress state of TiAlTaN/AlCrN multilayer coatings as a function of coating thickness ranging from 1 to more than 20 µm. Various films were prepared by arc evaporation using different substrate types including hard metal, monocrystalline and polycrystalline Al2O3, monocrystalline MgO, and austenite. We found that residual stress peaks in the coatings are relieved by plastic deformation of soft substrate materials. Contrarily, significant residual stresses are built up with increasing coating thickness in the case of stiff substrate types. Additionally, the influence of the multilayer architecture on the residual stress state is discussed. The residual stress state was determined using the sin2Ψ method. Film growth morphology and structure were characterized using cross sectional scanning electron microscopy and X-ray diffraction, and the mechanical properties like hardness and indentation modulus were analysed by nanoindentation.

Resume : Aluminium oxide is highly valued for many applications due to its exceptional thermo-chemical properties and exhibits – in case of the thermodynamically stable corundum (α) structure – also a high hardness and adequate wear resistance. At deposition temperatures lower than 800 °C, transient oxides, as for instance the γ-Al2O3 phase, are more likely to crystallize during vapour deposition. Even though considerable progress has been made in the last years by the synthesis of (Al,Cr)2O3 solid solutions with corundum-like properties, the deposition of single-phased α-Al2O3 coatings at lower temperatures via physical vapour deposition still poses a great challenge and thus demands further investigations. With the objective to shed further light on the formation of (Al,Cr)2O3, we investigated the structural evolution of intermetallic Al1-xCrx and substoichiometric Al1-xCrxOδ films (with x = 0.1, 0.25, 0.3, 0.50, 0.75), deposited by cathodic arc evaporation, and their oxidation behaviour. The phase composition of our coatings is dominated by Al13Cr2, Al8Cr5, or AlCr2 next to Al and Cr. At low oxygen flow rates during the deposition, the oxide formation proceeds via a distinct refinement of the initially pronounced columnar microstructure. We can show that both, the Al/Cr-ratio as well as the oxygen content of the coatings and their morphology significantly influence the scale formation during post deposition oxidation at temperatures between 900 and 1050 °C.

Resume : W-Cu thin films were developed using the GLAD co-sputtering technique. The films were produced with two separated W and Cu targets. Both targets were focused on the centre of the substrate and were simultaneously sputtered using opposite and oblique particle incidence angles of 80° from the substrate normal. W and Cu target currents were inversely changed from 50 to 140 mA, so as to tune the elemental concentrations and the microstructure. A shield was added between the W and Cu targets, perpendicularly to the substrate surface, in order to prevent the cross-contamination of the targets. This shield also favors the collimation effect of the W and Cu sputtered particles. Similarly, two argon sputtering pressures were used (0.42 and 1.0 Pa) with and without the shield. The W/Cu weight concentration ratio varied between 0.65 and 20 as a function of the sputtering pressure and target currents. The role of the shield was clearly evidenced and allowed significant variations of the W/Cu ratio. SEM analysis showed a tuneable inclined columnar microstructure. The crystallographic structure (phase occurrence, crystal size) was also influenced by the shield implementation and sputtering pressure. The wide range of DC electrical resistivities (3.6x10-7 to 5.7x10-5 Ohmm) exhibited by these co-sputtered films was discussed considering W and Cu target currents, high and low sputtering pressures and the use or absence of a cross-contamination shield. Keywords: W-Cu films, GLAD co-sputtering, composition, electrical resistivity, microstructure.

Resume : Many industries are recently focused on the development of the inkjet printing technology as well as the appropriate nanoparticle metallic inks for the fabrication of electronic devices. Among conventional metallic inks used in the printing process, silver ink is a typical metallic ink having high conductivity and thermal stability. However, there is a limitation to use it in the fabrication due to its high material cost. Copper is considered as a substitute material for replacing silver, but copper ink has an oxidation issue under atmospheric conditions. Cost effective, highly conductive, and oxidation-free copper nanoparticle ink was synthesized in this study. Copper complexes and copper nanoparticles were used in the synthesis to prevent its oxidation. Expanding its application to various substrates, the synthesized nanoparticles were thermally treated at relatively low temperatures in the range of 200~500℃. The prepared copper ink was printed on the silicon substrate and the printed film was then characterized. Resistivity of the printed electrode was calculated from the cross-sectional area measured by a profilometer and resistance was measured by a digital multimeter. Surface morphology of the prepared electrode was also analyzed using scanning electron microscope (SEM) and atomic force microscope (AFM). From our results, the synthesized copper ink showed the suitable properties to apply to inkjet printing process for the fabrication of various electronic devices.

Resume : Thick multilayer (up to 5 layers with a 5 μm thickness each) Zr-B-C, Zr-B-Si-C and Hf-B-Si-C coatings were deposited on silicon and steel substrates using pulsed magnetron co-sputtering of single B4C-Zr(Hf)-(Si) target (at a fixed 15% Zr or Hf fraction and a varying 0-7.5% Si fraction in the target erosion area) in pure argon. A planar unbalanced magnetron (127 × 254 mm2) was driven by a pulsed dc power supply operating at a repetition frequency of 10 kHz with a fixed 85% duty cycle (voltage pulse duration of 85 μs). The total pressure was 0.5 Pa and the substrate temperature was adjusted to 410 °C during the deposition on the substrates at a floating potential. Prior to each deposition of a 5 μm thick layer, a modification of the substrate surface was performed by pulsed dc magnetron sputtering of the B4C-Zr(Hf)-(Si) target in argon at the same pressure of 0.5 Pa, a duty cycle of 20% (voltage pulse duration of 20 μs), a negative dc substrate bias of 1200 V and the substrate temperature of 410 °C for 90-180 min. It was shown that the pretreatment of the steel substrates is a necessary condition for adhesion of the multilayer Zr-B-C, Zr-B-Si-C and Hf-B-Si-C coatings. All coatings possessed a high hardness (up to 32 GPa), high elastic recovery (>70%) and H/E* ratio around 0.1. The 16 μm thick Zr-B-Si-C and Hf-B-Si-C coatings exhibited an enhanced erosion resistance in industrial tests simulating the liquid impact erosion of moving steam-turbine blades.

Resume : There is an urgent need to develop efficient and cost-effective catalyst for hydrogen evolution reaction (HER) in order to realize a hydrogen economy with clean and renewable energy. Nanostructures of layered transition metal dichalcogenides show promising electrocatalytic activity towards hydrogen evolution reaction, however, majority of the exposed surfaces (basal plane) are inactive, and, engineering their catalytically active edge sites still remains a challenge.[1-2] Here we show that monodisperse single/few-layered MoSe2 nanocrystals can be directly deposited onto any conducting substrate, through electrochemical exfoliation of bulk MoSe2, which exhibit remarkable electrocatalytic activity for the HER with ultra-high efficiency showing very low on-set potential (7 mV vs. RHE) and Tafel slope (31.8 mV dec-1) and good stability after 2000 cycles of CV scans.[3] The exceptional electrocatalytic activity of MoSe2 nanocrystals is resulted from the synergistic advantages emerging from improved edge sites, enhanced electronic conductivity by the presence of co-existing MoO3-x and the presence of new and active sites arising upon in-situ lithiation, all in one step, which is facile, economic and environmentally benign.[4] [1] S. S. Chou, N. Sai, P. Lu, E. N. Coker, S. Liu, K. Artyushkova, T. S. Luk, B. Kaehr, C. J. Brinker, Nat. Commun. 2015, 6. [2] D. Gopalakrishnan, D. Damien, M. M. Shaijumon, ACS Nano 2014, 8, 5297-5303. [3] D. Gopalakrishnan, D. Damien, B. Li, H. Gullappalli, V. K. Pillai, P. M. Ajayan, M. M. Shaijumon, Chem. Commun. 2015, 51, 6293-6296. [4] D. Damien, A. Anil, D. Chatterjee, M. M. Shaijumon, J. Mater. Chem. A (Under revision) 2016

Resume : ZnO has gained substantial interest in different research fields due to its attractive properties and wide range of applications. For instance, ZnO is a promising material in photocatalysis applications for water treatment and disinfection. Furthermore, the quantum confinement effect has been widely studied in ZnO nanostructures. The observation of such a phenomenon requires to reach highly crystalline nanostructures with low dimensions. Especially, ultrathin ZnO nanowires have attracted much attention. In this study, the synthesis of ultrathin, single-crystalline zinc oxide nanowires was achieved by treating in a flowing microwave plasma oxidation process zinc films coated beforehand by a sputtered thin buffer layer of copper. The aspect ratio of the nanowires can be controlled by the following experimental parameters: treatment duration, furnace temperature, oxygen concentration. An average diameter of 6 nm correlated with a mean length of 750 nm can be reached with a fairly high surface number density for very short treatments, typically less than 1 minute. The oxidized samples are characterized by means of SEM, XRD, SIMS, HRTEM and EDX techniques. Nanowires are only composed of ZnO without copper particles inside or at the end of the nanowires. Temperature-dependent photoluminescence measurements confirm that ZnO nanowires are of high crystalline quality and thin enough to produce quantum confinement.

Resume : Pulsed laser deposition (PLD) enables the epitaxial growth of crystalline films using material transfer, from a target to a substrate, via a plasma-plume created during laser ablation. Owing to the several experimental controls available in PLD, which can be adjusted during deposition, this is an excellent tool for growing designer films through altering film parameters such as stoichiometry, crystallinity and thickness [1, 2]. We will present the effects on the refractive index of thin garnet films grown via PLD when varying the temperature of the substrate, onto which the films are grown. Our results show that monotonic control of the YGG refractive index with substrate temperature is possible whilst maintaining good crystal properties. It was observed that at higher substrate temperatures, the gallium content in the crystal is reducing, supported by EDX and XRD measurements, which leads to a decrease in the refractive index of the film. This technique can therefore be used for the fabrication of advanced devices with bespoke refractive index profiles and engineered dielectric properties of composite materials. 1. J. A. Grant-Jacob et al. Opt. Mater. Express 6, 91-96 (2016) 2. T. L. Parsonage et al. Opt. Express 23, 31691-31697 (2015)

Resume : Cluster sources based on magnetron sputtering and gas aggregation processes are versatile tools for producing nanoparticles since they allow easy variation of process parameters. In this work, we present results regarding the synthesis of tungsten nanoparticles (WNPs) with very different shapes using a cluster source operated with argon. During the study the working gas pressure and the aggregation length were kept constant while the characteristics of the radiofrequency power applied to the magnetron discharge were modified. Both continuous and rectangular pulsed waves were used: the applied power was 60 W and 100 W in continuous mode while in the pulsed mode the mean power was 60 W (tON = tOFF = 0.2 s). The WNPs were investigated by Electron Microscopy and X-ray Diffraction. The WNPs obtained in continuous mode show a flower-like (60 W) and concave hexapod (100 W) shapes, both presenting dendritic growth. In contrast, the pulsed mode leads to single crystalline cube-octahedral WNPs. All types of WNPs contain both αW (stable) and βW (metastable) phases. The βW phase is dominant in the concave hexapod WNPs and it is remarkable to note the stability of this phase over two years. These results show the ability of this method to produce WNPs with desired shapes for specific applications. Acknowledgements: This work has been financed by the Romanian Ministry of Research and Innvation in the frame of Nucleus programme 4N/2016, and the France-Romania project IFA-CEA C5-07/2016.

Resume : Copper nanocrystals (Cu NC) are actively investigated as substitutes for costly silver nanocrystals in conductive inks. However, to be of any use for printed conductors, oxidation of Cu NCs to non-conductive copper oxides must be avoided. Here, we analyze the interplay between the Cu NC surface termination, oxidation suppression and bulk copper formation through thermal annealing using 3 nm Cu NCs synthesized via thermal decomposition of copper formate in oleylamine (OLA). By adapting the method introduced by Sun et al,1 we obtain stable Cu NC dispersions that do not oxidize when stored under inert atmosphere, while showing a rapid conversion into copper oxide when exposed to air or deposited to form a thin NC film. Using solution 1H NMR spectroscopy, we demonstrate that as-synthesized Cu NCs are capped by OLA. OLA is tightly bound at NMR time scales, yet slowly desorbes during storage of the Cu dispersions, a process that is accelerated by oxygen exposure. Addition of carboxylic acids leads to the displacement of OLA from the Cu NCs and the formation of a denser ligand shell, probably consisting of dissociated carboxylic acids. We demonstrate that carboxylic acid ligands make Cu NCs more oxidation proof and facilitate the conversion of films of oxidized Cu NCs into a dense copper film. This offers the prospects of using colloidal Cu NCs as main constituent in conductive, nano-copper inks for applications in printed electronics. (1) Sun, X. et al. Small 2005, 1 (11), 1081?1086.

Resume : Even though CuS shows good solar radiation absorbing properties, till now, only few reports were focused on CuS thin films with applications in solar thermal energy conversion. In this work, colored (green) solar selective absorbing coatings Al/Al2O3/CuS were obtained by electrochemical (Al2O3) and spray pyrolysis (CuS) deposition techniques.To improve the coatings’ efficiency, the number of spraying sequences was varied from 5 to 15. Additionally, the effect of a TiO2 anti-reflection and anti-photocorrosion layer on the solar selectivity and stability of the absorbing coating was investigated. The CuS coatings optical properties (solar absorptance, αs, and thermal emittance, εT) were correlated with the chemical composition, crystalline structure and morphology. The results show that samples morphology, homogeneity and porosity (and consequently αs and εT) are significantly influenced by the coatings thickness and density, thus the number of spraying sequences used for CuS film deposition. Solar selective absorbing coatings, with αs ranging from 0.79 to 0.95 and εT = 0.36 - 0.66, were obtained. Durability tests (temperature, UV irradiation and saline aerosols) on the best performing coating, with or without TiO2 layer, evidenced a significant photocorrosion protection and a limited influence on the optical properties. These effects are also depending on the TiO2 layer thickness being recommended a very thin layer which still preserves surface homogeneity.

Resume : Nanostructured multilayer thin film architectures on the base of FePt system, the influence of heat treatment atmosphere on transformations in [FePt(15 nm)/Au(7,5 nm)/FePt(15 nm)]2x nanothickness multilayer thin films, correlation between nanostructure and functional magnetic and other properties of such nanocomposits were investigated. Films were obtained by magnetron sputtering onto SiO2(100nm)/Si(100) substrates under room temperature and post-annealed at 300°C – 900°C in Ar and Ar + H2 (3 vol.%) atmospheres for 30 s. By synchrotron structural analysis and magnetic properties measurements it was shown that A1-FePt→L10-FePt phase transformation takes place at 500°C irrespective to the heat treatment atmosphere composition. Annealing in Ar atmosphere leads to degree of L10-FePt phase ordering and lattice tetragonal distortion increasing comparing to annealing in Ar + H2 (3 vol.%) atmosphere. Herewith, when hydrogen presences in heat treatment atmosphere this leads to thermal stabilization of L10-FePt grains size (as it was determined by atomic-force microscopy). Heat treatment in Ar + H2 atmosphere leads to post-annealed coercitivity increasing probably due to hydrogen influence on exchange decoupling of FePt grains. Possible models of structure visualization during processes investigated and new trends in thin film materials of such kind are discussed.

Resume : Using characterization methods at the nanoscale the correlation between nanostructure of nanothickness V, V/Ag thin films and physical (electrical) properties was investigated. On the basis of these data visualization models of structure and phase composition formation in V(25 nm) and V(25 nm)/Ag(25 nm) thin films during annealing in vacuum 10-3 Pa and 10-7 Pa up to 600°C have been proposed. Films were deposited by PVD electron-beam sequential evaporation in 10-7 Pa vacuum onto SiO2 (001) substrates. According to in-situ electron diffraction characterization the tetragonal distortion of vanadium bcc phase with oxygen solid solution in vanadium (β-phase) formation takes place during films annealing at 400°C in 10-3 Pa vacuum. The vanadium monoxide VO is formed from this phase at temperature of 600°C. Vanadium bcc phase transformation into body-centered tetragonal β-phase within temperature range 400–600°С was analyzed in SPring-8 synchrotron center (beamline BL44B2). The tetragonality is manifested by splitting of (110) vanadium reflection in (101) and (110), (200) reflection – in (002) and (200). The degree of tetragonality depends on annealing temperature and concentrations of O and Ag in V film. The influence of additional Ag layer on nanostructure of V thin films and physical (electrical) properties was studied as well.

Resume : Unusual electrical and magnetic behaviour of graphene and graphene oxide thin films For more than decade research of graphene and graphene-related materials create a huge interest due to its electronic, optical, magnetic and other properties [1]. Besides interest of fundamental science, graphene and graphene oxide thin films can be part of future electronics devices. It is necessary to develop methods for characterization of electronic and magnetic properties of such thin films. Magnetoresistance measurement is one of such characterization methods. Magnetoresistance, which reflects magnetic dependence of material resistivity, is one of essential effects for manipulating spintronic devices. Magnetoresistance in graphene is usually have very low values in room temperature and low magnetic field. In most experiments magnetoresistance in graphene was shown in the scale of high magnetic field and/or very low temperature [2]. We demonstrate magnetoresistance in room temperature and low magnetic field on mechanically exfoliated bilayer graphene deposited on hexagonal boron nitride. We propose explanation for our results. [1] Geim, Andre K., and Konstantin S. Novoselov. "The rise of graphene." Nature materials 6.3 (2007): 183-191. [2] Gopinadhan, Kalon, et al. "Extremely large magnetoresistance in few-layer graphene/boron-nitride heterostructures." Nature communications 6 (2015)

Resume : New technologies are required to precisely structure glass materials. In this paper we present results attained with a polarised short pulse laser to create nanometre periodic structures on the glass. Transparent glass samples of 0.8 mm thickness were initially coated by DC sputtering with Indium tin oxide (ITO) of 175 nm thickness. A laser of 1030 nm wavelength with 10 ps pulse duration operating at 400 kHz was used. A beam scanning system was used to deliver the laser to the coated sample surface using 100 mm focal length lens. For optimal beam shapes and pulse to pulse stability, the laser was operated at maximum power and attenuated using external attenuator. The laser pulse overlap on the ITO film was controlled by adjusting the speed of steering mirrors of galvanometer based beam scanning system and the repetition rate of the laser. The sample was placed on a 3D computer controlled stage which enabled the positon of sample and lens to target distance to be changed with micrometre accuracy. The applied fluence was varied from below the visible damage threshold from 0.4 Jcm-2 of ITO to 1.5 Jcm-2 with multipulses (1 to 30 laser shots per area). At first, periodic nanostructures are generated on ITO films with period 260 nm, corresponding to the forth of incidence laser frequency. With increasing the incident laser fluence or higher SPA, the ITO film is removed and is completely removed at 1.04 J/cm-2 with 25 SPA without effecting or damaging the underlying glass surface. Nanostructures with same period are subsequent generated directly on the glass surface for higher fluences (1.07 Jcm-2) following removal of ITO film. Two type of structures are found, first type with 260 nm period is completed after the forth pulse and is independent of applied fluence. This initial structure evolves to a second structure which is clearly polarisation dependent and starts to grow after the 5th pulse and is firmly established after 12-15 pulses. The ability to structure glass using a laser process offers new opportunities for inexpensive microsystems development.

Resume : Topological insulators (TIs) have generated a great interest in the fields of condensed matter physics, chemistry and materials science. A topological insulator is a material that is electrically insulating in the bulk, while possessing highly conductive and spin-polarized massless Dirac surface states that are protected against disorder by time-reversal symmetry (TRS), allowing for near dissipation-less transport of spin on the surface [1]. The TRS can be broken by, for example, using elemental doping to induce a magnetic phase in the material. The broken time-reversal symmetry allows for the formation of an energy gap on the surface and is important for many interesting properties in these materials [2]. The second generation 3D TI Bi2Se3 is a class of such materials. To enable a multitude of possible applications of these materials, it is necessary to open a surface energy gap as well as keep the Fermi energy inside the bulk gap [3]. It has been proposed in the literature that doping TIs by magnetic transition metals, such as Fe, Mn, Cr and Co, could break the TRS and open a surface gap [4]. These magnetic impurities also induce electrical doping effect with magnetic effect, i.e., the substitution of Fe 2+ or Co2+ for Bi3+ create hole dopants into the material. On the other hand, when dopants are rare earth metals such as Dy, which are trivalent, only magnetic moments are introduced. The binary compound Bi2Se3 is very popular for TI studies as it has a relatively large bulk bandgap ( ? 0.3 eV) compared with other TIs. One attractive direction in the research is the use of nanostructures, wherein the ratio of surface area to volume is much higher than in bulk materials so that the total conduction from the bulk region is lower, allowing observation of the surface states in certain transport measurements. There is no study performed on rare-earth-metal doped topological insulator nanostructures. In the present study, we synthesized Dy-doped Bi2Se3 nanoplates by a solvothermal reaction. The as-synthesized nanoplates show uniform hexagonal morphology of about 0.16 ?m size and ~ 15 nm thickness. A physical property measurement system (PPMS) is used to determine the temperature dependent magnetization in zero-field cooled and field-cooled cycles between 2 K and 300 K. The doped nanoplates are found to be paramagnetic in the whole temperature range. We also measured the magnetic susceptibility as a function of temperature and found that the effective magnetic moment per Dy is 9.64 ?B, which is close to full moment (10.64 ?B) expected from Hund?s rule. Further experimental and computational studies of electronic and magnetic properties of the system are under way. References: [1] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010). [2] J. Wang, X. Chen, B.-F. Zhu, and S.-C. Zhang, Phys. Rev.B 85, 235131 (2012). [3] X. L. Qi, T. L. Hughes, and S. C. Zhang, Phys. Rev. B 78, 195424 (2008). [4] Q. Liu, C. X. Liu, C. Xu, X. L. Qi, and S. C. Zhang, Phys. Rev. Lett. 102, 156603 (2009).

Resume : Phase-Change materials (PCM) have a great potential for memory device applications in Phase-Change Random Access Memory. The storage mechanism is based on the quick and reversible change in properties between amorphous and crystalline states. X-ray scattering is the adapted tool to investigate in details such a phenomenon. The two states can also be distinguished by following the large contrast in optical reflectivity and electrical resistivity. During the amorphous-crystalline phase transition with temperature, strain and defects accumulation are expected and may contribute to the fatigue of cell memory structure during their functioning (cycling). The possibility of down-scaling PCM requires a better understanding of the phase transition mechanism in order to determine more precisely the relation between strain, surface energy, atomic structure and size as a function of the temperature. The aim of this work is to address the physical phenomena involved during the crystallisation of thin and ultrathin films of chalcogenides. GeTe films (100 down to 5 nm) have been investigated in situ during annealing using coupled i) X-Ray Diffraction, ii) optical curvature and reflectivity measurements, iii) X-Ray Reflectivity, iv) Pair Distribution Function. The experimental approach will be presented and a fine analysis of the amorphous ? crystalline phase transition (in terms of crystallisation temperature, strain, etc.) will be detailed. [work funded by ANR-15-CE24-0021 SESAME project]

Resume : For several decades, nanoscaled thin-films and coatings played vital roles in modern technologies such as in micro- and nanoelectronics. Moreover, the concept and practice of tailoring the structure and morphology of a given coating or thin film system to modify its properties has been long used to add new functionalities and improved behavior to several materials and devices. Nano-engineering of surfaces is playing a fundamental role in this particular area of research, either in the case of new materials development or in their modification. It is known that even at low temperatures when bulk diffusion processes are practically frozen almost full intermixing of components in thin film heterostructures can occur through grain boundary diffusion and grain boundary diffusion induced motion. In this study, the low-temperature diffusion in Pt/Au/Fe nanolayers was investigated. XRD analysis and SNMS investigation showed that the introduction of an additional intermediate Au layer leads to an enhancement of the low-temperature intermixing of nanocrystalline Fe and Pt thin films. The intermixing at relatively low temperatures is caused by the grain boundary diffusion induced reaction layer formation mechanism. At the same time the ordering is also enhanced, leading to the appearance of the chemically ordered FePt phase, which results in a strongly increased coercivity. At the same time the enhanced chemical ordering is interpreted by stresses developed during the formation of the disordered FePt phase along the grain boundaries: in some of the new grains formed, where there is compressive stress along the {100} directions, chemical ordering can take place.

Resume : Thin film metallic glasses (TFMG) have recently emerged as alternative materials for many applications (micro-electro-mechanical systems and biomedical use), owing to their unique characteristics such as large elastic limit, high toughness and high corrosion resistance. These characteristics are related to their microstructure that lacks long-range-order atomic periodicity and amorphous texture. However, if the mechanical properties of the TFMGs have been largely studied, just few studies have been focused on the understanding of their microstructure evolution during heating. In order to investigate the thermal stability of antibacterial magnetron-sputtered Zr-Cu and Zr-Cu-Ag TFMGs [1], the present study proposes a multiscale characterization involving in situ techniques. First, the crystallization behavior and structural stability were investigated by in situ high temperature XRD combined to DSC experiments, during a continuous heating from room temperature to 600°C under vacuum. Moreover, due to the fast diffusion of silver, silver-based coatings are subject to dewetting. Such process, leading to the formation of micrometric segregated micrometer-sized domains, was observed in situ by using HT-environmental SEM. Finally, at a deeper nanometric scale, in situ HT-TEM was used to observe, during heating, the progressive formation of crystallized grains from the initial amorphous matrix. Through such a multiscale in situ approach, we should better understand the general evolution of the TFMGs under thermal constraint. [1] A. Etiemble et al., Innovative Zr-Cu-Ag thin film metallic glass deposited by PVD magnetron sputtering for antibacterial applications, J. Alloys and Comp. (2016), doi: 10.1016/j.jallcom.2016.12.259.

Resume : The selective detection of flammable and/or toxic gases (e.g. CO), using optical sensors is presently a raising trend over the well-established conductometric-based methods. The present work proposes a reliable and effective possibility of an active material suitable to be used in an optical sensor. It is based on nanocomposite films, containing Au nanoparticles embedded in an oxide matrix. The gas detection mechanism and resolution of the films will be tailored according to the Localized Surface Plasmon Resonance (LSPR) phenomenon revealed by these materials, which is strongly dependent on the composition, distribution, size and clustering tendency of the Au nanoparticles, as well as on the dielectric medium surrounding them. The local changes in the refractive index, such as the ones induced by gas species interacting with superficial nanoparticles, will be used to monitor the LSPR band shifts observed in optimized thin films. Copper oxide (CuO) has been reported to be sensitive to gas molecules, revealing important physical interactions with selected molecules, such as CO. This suggests that it might be an important host for the plasmonic nanoparticles and thus for the detection of gas molecules. In the present work, a set of Au/CuO nanocomposite films were prepared to enable the attainment of gas sensitivity by the tailoring of the nanoparticles growth and coalescence. Preliminary results showed a progressive growth of the Au nanoparticles, together with some crystallization of the dielectric matrix when the annealing temperature was increased. A noticeable nanoplasmonic effect was found for selected thin films and for temperatures higher than 400°C, which will be correlated with their sensing properties.

Resume : Graphene oxide (GO) is a potential precursor for graphene. The electrochemical reduction of GO is a potential low-cost and green approach. The cathodic deposition is based on the reduction of GO to reduced graphene oxide (rGO) with reduced solubility accompanied by hydrogen evolution blocking further adsorption of rGO [1,2]. The mechanism of the reduction, as well as the final structure of the reduced form have been the focus of the present study. The reduction of GO was investigated by an spectroelectrochemical in-situ approach. The generation and degeneration of oxygen containing groups and C=C bonds were followed via FTIR spectroscopy. Multivariate Curve Resolution was used to interpret the results. The possibility of controlling the composition and structure of rGO is discussed. [1] M. Pfaffeneder-Kmen, F. Bausch, G. Trettenhahn, W. Kautek, J. Phys. Chem. C 120, 15563?15568 (2016). [2] M. Pfaffeneder-Kmen, G. Trettenhahn, and W. Kautek, J. Phys. Chem. C, 2016, submitted.

Resume : Cyclopropylamine, an isomer of widely known allylamine, is a promising candidate for deposition of amine-rich coatings thanks to the low toxicity, excellent stability of prepared coatings and relatively high content of amine groups. However, for further optimization and up-scaling of the process a deeper understanding is crucial. The presented work investigates some fundamental aspects of the deposition process by plasma diagnostics and discusses it within scope of the macroscopic kinetics. The gas phase processes are investigated by mass spectrometry and optical emission spectroscopy, whereas surface processes, mainly the ion bombardment, are studied by retarding field energy analyzer. This work provides insight into the correlation between the inner plasma parameters obtained from diagnostics and properties of the thin film characterized namely by X-ray photoelectron spectroscopy and infrared spectroscopy. Finally, the link between the external parameters and desired thin film properties can be established.

Resume : Abstract: Composition induced quantum phase transition have been found in many alloys. The metallic Pd1-xNix alloy system is one of them. It shows a paramagnetic to ferromagnetic quantum phase transition at a critical concentration xc ~ 0.026 in bulk [1] and in nano dimension [2]. It is well known that when a magnetic impurity couples with conduction electrons, spin-flip scattering known, as the Kondo effect gives rise to an anomalous component of the resistivity at low temperatures. Graphene, a two dimensional structure, is an ideal system to study the Kondo effect owing to its high conductivity. Some experiments suggest that adatoms, vacancies or defects on graphene work as local moments which are usually responsible for its magnetism [3], and sometimes for its the Kondo behaviour [4]. In the present work, we synthesize graphene oxide (GO) by Hummer’s method [5], reduce it to reduce graphene oxide (rGO) using hydrazine hydrate and disperse Pd1-xNix nanoparticles during the synthesis of reduced graphene oxide (Pd1-xNix/rGO) nanocomposites. Chemical reflux method is used to adsorb the Pd1-xNix nano particles on the graphene sheet. After this formation and determination of nanocomposite phase, cystallinity, size and composition has been confirmed by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy respectively. Magnetic and transport properties of magnetic Pd1-xNix/rGO at low temperature have been measured using physical property measurement system (PPMS). The room temperature M-H plot shows the diamagnetic nature of nanocomposites but, below room temperature, it exhibits the paramagnetic behaviour. On the other hand transport measurements revealed the decreasing nature of resistivity on increasing temperature. Acknowledgement: The work at Department of Physics, IIT Kharagpur was supported by MHRD, India. References [1] Nicklas M., Brando M., Knebel G., Mayr F., Trinkl W., and Loidl A. Phys. Rev. Lett. 82, 4268, (1999). [2] Swain P., Srivastava K. Suneel and Srivastava K. Sanjeev Phys. Rev. B 91, 045401, (2015). [3] Chen, J. H., Cullen W. G., Jang C., Fuhrer M. S. & Williams E. D. Phys. Rev. Lett. 102, 236805 (2009). [4] Chen H. Jian et al., Nature Phys, 1038, 1962, (2011). [5] Kuo D., Chang C., Su T., Wang W., Lin B., Materials Chem. and Phys, 85, 201, (2004).

Resume : The aluminium scandium nitride AlxSc(1-x)N is an interesting material due to a number of potential applications which could be developed in micro electromechanical systems (MEMS). It has been reported that chemical compound influences the physical properties of the mixture, Akiyama et. Al. have observed a maximun piezoelectric response of 27.6 pC/N for a concentration of ~ 40% of Sc in the AlxSc(1-x)N film grown on silicon substrate 1. In this study, we have investigated the crystalline structure, electrical and optical properties of the AlxSc(1-x)N thin films deposited onto MgO and Pt/TiO2/SiO2/Si substrates. Radio frequency magnetron reactive co-sputtering system has been used for films deposition and a large range of concentration has been studied from pure AlN film to pure ScN film. The crystal structure and orientation of the films were investigated by XRD analysis and electrical properties examination was performed with a Physical Property Measurement System (PPMS) and a spectroscopic ellipsometry technique. Also, piezoelectric responses were measured by Piezoresponse Force Microscopy (PFM). The obtained results suggest that AlxSc(x-1)N thin films with a value of x of ~40 % have a high piezoelectric response. This finding is particularly interesting for a development of a magnetoelectric compositie devices where AlxSc(1-x)N thin films might be utilized in piezoelectric components. Acknoweledgments : The work was supported by research infrastructure SAFMAT LM2016088 and by the JoEo Purkyně followship award to V. Mortet. Reference: 1 M. Akiyama, K. Kano, and A. Teshigahara, Appl. Phys. Lett. 95, 162107 (2009).

Resume : The conversion or absorber layer is of the most importance for solar cell efficiency therefore controlling its band gap plays an essential role in solar cell industries. In this paper, we present the modification of the band gap of a mixed phase of copper-indium-gallium-diselenide (CuIn1-xGaxSe2) nanoparticles synthesized with a solvothermal method. By increasing the amount of gallium in the structure, the band gap has been increased. Structural and morphological properties of the CIGS nanoparticles were determined by X-ray diffraction spectroscopy, scanning and transmission electron microscopy. Band gap tuning of CIGS thin films could be interesting for optimization of absorber layers in solar cells by enhancing the light absorption from the solar spectrum both in the visible and the ultra-violet range.

Resume : Surface-enhanced fluorescence (SEF) is observed from molecules located at a certain distance from plasmonic nanostructures that can strongly interact with adjacent fluorophores and it is function of several variables: nanoparticle size and shape, distance between chromophore and nanoparticle, plasmonic surface, and degree of spectral overlap between the chromophore emission and the surface plasmon extinction of nanoparticles. This work reports the use of gold shell-isolated nanoparticles (AuSHINs) to demonstrate an experimental variable for shell-isolated nanoparticle-enhanced fluorescence (SHINEF): tuning the distance between the chromophore and the nanoparticle core by increasing the shell thickness. In previous work we demonstrated that large AuSHINs (Au core size: 100 nm) produce higher enhancement factors (EF) for SHINEF applications than smaller AuSHINs (Au core size: 40 nm), both for 10 nm silica shell thickness. The findings were supported by finite difference time-domain calculations. Now, tuning the thickness of silica shell (0, 4, 7 and 10 nm) surrounding the large AuNPs (core size: 100 nm) allowed achieving different surface-enhanced phenomena, from surface-enhanced Raman scattering (SERS) to SHINEF. AuNPs and AuSHINs were spread onto an Langmuir-Blodgett monolayer of zinc(II)-protoporphyrin(IX) dimethyl ester resulting in SERS EF ~ 103 for AuNPs and SHINEF EF = 18, 23 and 29 for AuSHINs with 4, 7 and 10 nm of silica thicknesses, respectively.

Resume : The deposition of diamond films on hardmetal (WC-Co) substrates requires prior preparation of the substrate in order to passivate cobalt and thus prevent the formation of sp2 C-bonds instead of sp3. This formation of graphite compromises the mechanical properties of the interface between the diamond film and the substrate, causing lack of adhesion of the coating. Several methods are used to remove cobalt or hinder its surface segregation, such as acid pretreatments or metallic carbide interlayers between the substrate and the diamond film. In this work we developed in-situ tungsten/titanium carbide interlayers and compared them with a commonly used acid pretreatment (Murakami followed by H2SO4/H2O2) on hardmetal. This is a new, environmentally friendly, one-step approach, allowed by the flexibility of HFCVD reactors, that precludes the use of acids and ensures the high adhesion required by machining operations. The effect of the substrate temperature cycle on adhesion, growth rate and micro- and nanocrystalline diamond quality was also studied using drill bits and end mills tools as substrates. The diamond film adhesion was measured by indentation tests on square hardmetal plates and by drilling tests on MMC parts. The development was closely followed in every step with a characterization of the coated sample by µ-Raman spectroscopy and scanning electron microscopy.

Resume : In view of fact that the pure spin Hall magnetoresistance (SMR) effect was only observed in nonmagnetic metal (NM)/ ferromagnetic (FM) insulator systems such as YIG/Pt and Pt/CoFe2O4, a FM insulator-based hybrid structures came in to focus [1]. Much attention has been given to the SMR phenomena in NM/FM oxide structures due to their applicability to the control of the magnetization direction via the in-plane current. Here, we report the anomalous Hall resistance and the anisotropic magnetoresistance (AMR) of Pt bars deposited on Fe3O4/MgO/Ta multilayer stacks on top of unetched Si substrates. The temperature dependence of the AMR in a set of Pt/Fe3O4/MgO/Ta hybrid structures was explored as a function of Pt thickness ranging from 2.0 and 4.0 nm and Fe3O4 thickness ranging from 2.0 and 40.0 nm. In order to determine the spin mixing conductance at the Pt/Fe3O4 interface, magnetization orientation dependent magnetoresistance (MR) was carefully analyzed. The AMR was obtained ~ 0.1 % at 100K below the Verwey transition temperature for a 2.0-nm-thick Pt film grown on a 40-nm-thick Fe3O4 film, in which a much higher MR ratio was seen than samples with thicker Pt thickness. However, the Fe3O4 thickness dependence of the AMR did not clearly reveal. Intriguingly, the spin mixing conductance at the interface is found to be different depending on the structural and electrical properties of Fe3O4 thin films. Therefore, the effect of the roughness and crystallinity of the Fe3O4 films on the AMR behavior were also investigated as well. [1] M. Weiler, M. Althammer, F. D. Czeschka, H. Huebl, M. S. Wagner, M. Opel, I. Imort, G. Reiss, A. Thomas, R. Gross, and S. T. B. Goennenwein, Physical Review Letters 108, 106602 (2012)

Resume : The development of transparent conducting coatings as thin film-electrodes with interesting physico-chemical characteristics like high electron work function, high electron mobility and high transparency, hence, is becoming more relevant. Indeed, to meet these forthcoming requirements, novel alloys or cost-effective preparing techniques are in demand. One of these approaches is focusing on a preparation of ternary oxides by the spray pyrolysis technique. This work deals with some physical studies on SnO2–ZnSnO (TO-ZTO) alloy sprayed nanofilms grown on sapphire substrates at different temperatures (450°C and 600°C). The structural and optical properties were investigated using X-Ray diffraction (XRD), UV visible spectroscopy and Photoluminescence (PL) techniques. XRD results reveal the existence of a mixture of SnO2/ZnSnO3 and SnO2/Zn2SnO4 phases at T=450°C and 600°C, respectively. The structural analysis shows that both phases are polycrystallines. On the other hand, the optical constants (refractive index, extinction coefficient and the dielectric constants) have been obtained by the transmittance and the reflectance data. The optical band gap energy value changed from 3.96 eVdown to 3.78 eV as substrate temperature increased from 450°C up to 600°C. The room temperature photoluminescence results reinforce this finding regarding the existence of three phases (SnO2, ZnSnO3 and Zn2SnO4) which is consistent with X-Ray diffraction analysis.

Resume : Plasmonic nanoparticles doping of solar cells improves power conversion efficiency. It is believed that it will be implemented in 4th generation solar cells. The metallic nanoparticles must be incorporated into the cell production, and this limits available annealing temperature range, since the cell is temperature sensitive itself. This leads to compromises in size and shape distribution widths of the plasmonic nanoparticles. Pulsed laser annealing is proposed as a solution: it is limited to the metallic film on top, and the energy for the deweting is supplied to it, leaving the structure below virtually unchanged, regardless the number of applied pulses. Here we report the study of laser annealed aluminium nanoparticle production. Magnetron sputtering at room temperature was employed in production of smooth Al films on monocrystalline silicon. The thickness of films was 10 nm. The films have been annealed by pulsed infra red laser. Pulse energy fluence was varied from 70 to 200mJ/cm2, and the number of pulses from 1000 to 10 000. The size distribution and uniformity of irradiated surface was invrstigated using AFM and GISAXS. The initial film was already nanostructured: its surface is one of densily packed nanopfeatures that are 1.6 nm high. After annealing with 5000 pulses of 120mJ/cm2 energy fluence, larger particles of irregular shape are grown, but they are surrounded by remnants of initial rough surface features. An even distribution of particles was produced when the number of pulses was increased to 10000. Lateral size distribution is significantly sharpened, while the height distribution remains relatively wide. A bimodal particle distribution was produced when th fluence was 150mJ/cm2. Generally, increment of fluence resulted in increased particles height, while the lateral dimensions did not change significantly.

Resume : Due to the high saturation magnetization and coercivity, permanent magnet with rare-earth components have been used in the industrial applications such as not only mechanical parts but also electrical and electronic products. However, rare-earth components have strong dependency on rare-earth elements limited and regionally concentrated supply. To overcome this problem, investigation of rare-earth free magnets are necessary. In this study, among rare-earth free magnetic materials, Fe16N2 films shown significantly high saturation magnetization on several previous papers were deposited on Si (001) by RF magnetron sputtering. A ratio of Fe16N2 in the Fe-N film affects saturation magnetization. However, even though film deposited with optimum deposition conditions (partial pressure of gases, power etc), films show different properties depending on thickness of the films. In this work, we investigated relation between magnetic properties and thickness. Crystallization and the ratio of Fe16N2 in the Fe-N film were measured by X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS). Magnetic properties were measured by Vibrating Sample Magnetometer (VSM). Surface morphology and a structure were shown with Field Emission Scanning Electron Microscope (FE-SEM).

Resume : The problem of structural steel corrosion occurs to a great extent, due to the increasing use in any kind of construction, while it worsens in areas with highly corrosive environments such as seaside and heavy snowfall regions due to the intense presence of Cl- ions. For the protection of structural steel hot-dip galvanizing is the most common coating technique and widely applied in industrial scale. The protection mechanism is based on the cathodic protection of the ferrous substrate from Zn and consists in converting the substrate in cathode of a galvanic element. The result is that oxidation reactions do not occur on the metal substrate, and thus it is protected. However, the protection potential of these coatings is significantly reduced in areas with high chloride concentration. In the present work the deposition of hot dip Zn coatings reinforced with oxide compounds is investigated. The specimens were dipped into a bath containing Zn, Al and metal oxide nanoparticles (Al2O3, TiO2, SiO2), in order to create oxide inclusions in the body of the coating, which act as a barrier against the diffusion of chlorides. The whole deposition setup was in a controlled Ar purged atmosphere in order to prevent the reaction of the molten metal bath with oxygen. The experimental data were acquired from Scanning Electron Microscopy (SEM) and X-Ray analysis (XRD). Furthermore an assessment of the corrosion resistance was made by electrochemical corrosion measurements.

Resume : Aluminum nanoparticles are deposited by the thermal evaporation method. During deposition the substrates are heated and maintained at fixed temperature (200-580°C). The used substrates are corning glass and crystalline silicon wafer oriented (100). Two series of samples are deposited one by varying the deposition temperature and the other the deposition time. The deposition is occurred at residual pressure less than 10-5 mbar. The evaporated aluminum rate is the same at each deposition thus the deposition time determine the deposited aluminum amount. The samples are characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and optical transmission in the uv-vis-ir range. The morphological parameters as nanoparticles size, density, and circularity are extracted using ImageJ program software. For all samples the SEM images show two kind of nanoparticles small and large with size around 10-20 nm and 60-150, respectively. The determined morphological parameters show coherent evolutions with the variation of the temperature of substrates and deposition time.

Resume : Zirconium oxynitride coatings are an interesting choice for aesthetic purposes, due to the combination of chemical stability, biocompatibility, good mechanical properties and a nice palette of colors achievable. Additionally, its preparation by reactive magnetron sputtering is relatively easy and simple. However, the chemical composition of films lays in a very particular region of the Zr-O-N ternary diagram, which is probably one the main reasons behind the limited palette of the observed colors. In this contribution, we will make a complete study of the Zr-O-N system, including an exhaustive comparison with literature. First, the deposition parameter space is explored, by changing target power, bias and composition of the sputtering atmosphere. The inclusion of Ti as dopant has been explored as well. The chemical and phase composition and structure of the films are evaluated by RBS, XRD and SEM, respectively, and correlated with the synthesis conditions. Finally, the color of the coatings is measured by spectrophotometry and interpreted in terms of the characteristics of the films.

Resume : Black aluminium thin films were prepared by means of pulsed DC magnetron sputtering. The films were deposited from pure aluminium target and their properties modification is reached by proper variation of deposition conditions, such as adding nitrogen to argon working gas of partial pressure from 0.5·10-3 Pa to 2·10-2 Pa. Black aluminium (it could be also referred as aluminium blacks) thin films exhibit, due to specific surface micro-nanostructure, excellent absorptivity in UV-VIS-IR electromagnetic radiation spectral regions. The film properties were examined by spectrophotometry, AFM, SEM, photoelectron spectroscopy. The deposition method allows effective, low cost fabrication of coatings on several kinds of substrates (eg. glass, stainless steel) and it is also suitable for large area substrates coating. Noble metal coating of black aluminum layer can be used toward further improvements on the properties mentioned above and to serve as its protection. The coating could find other application as absorbers of electromagnetic radiation, plasmonics, detectors, chemical sensors.

Resume : The intumescent coatings are passive fire protection of materials widely used for steel protection. The intumescent and subsequent char formation process helps to keep the steel temperature below its limiting temperature and to provide the fire-resistance. Our current research is based on studying the effects of adding silica sand nano-particles on epoxy based intumescent coatings. The effect of variation of 2,4, 6 and 8wt.% of silica sand nano-particles are blended in epoxy resins with fixed amount of hardeners. The prepared paste is deposited on mild steel grade 1020 by manual process. The prepared coatings are burned from four different corners to analyze the char microstructures with scanning electron microscope (SEM) with the help of EDX. The results showed the rapture surfaces and presence of holes, clusters and porous surface are due to the inappropriate mixing of silica sand nano-particles in char microstructures. The hardness of coating are determines that how much the coating withstand at specific force. The themo gravimetric analysis tells us about the weight loss percentage by increasing the temperature range; it also gives us information about thermal stability factors.

Resume : The GaAs based ferromagnetic semiconductor alloy compound containing Mn, Bi and In emerged as potential candidates for novel microelectronic and spintronic application. The (Ga,Mn)As has become a model diluted p-type ferromagnetic semiconductor, in which a few percent of Ga lattice atoms have been substituted by Mn atoms. All the epitaxial layers with the thicknesses up to 100 nm were grown using low temperature (230_C) MBE pseudomorphically on semi-insulating (001) GaAs and InGaAs substrates. The alloy compositions were determined using high resolution X-ray diffractometry (XRD) followed by the in-situ Reflection High Energy Electron Diffraction (RHEED). The quality of the epi-layers were estimated using transmission electron microscopy (TEM). The superconducting quantum interference device (SQUID) magnetometry have been used for the investigation of the magnetic properties of the heterostructures. Photoreflectance (PR) measurements were used the determination of the band gap (E0) and spin-orbit split-off (E_SO) band to conduction band optical transitions. The results presented in the our last publications concerning the ferromagnetic (Ga,Mn)As and bismuth doped (Ga,Mn)As, have shown the merit of the use the PR method for the band structure analysis of the GaAs base epitaxial layers. Besides the PR technique, the samples have been investigated by the ?Raman spectroscopy to confirm p-type character of some films by the observation of the Coupled Plasmon-LO Phonon Mode (CPPM). The in-situ UV Angle Resolved Photoemission Spectroscopy (ARPES) was used for the band structure analysis of the epitaxial layers.

Resume : Recently multilayer structures (MS) have found a wide range of applications, and one of the most specific of them is the X-ray standing wave (XSW) research technique for localization chemical elements in molecular layers [1]. The MS quality should be very high to meet all the requirements of application: few nanometers (1-10 nm) of individual uniform layer thickness, angstrom-smooth interfaces and number of layers up to several hundred. Additionally, the MS materials shouldn?t have secondary x-ray fluorescence in the region of interest. In this work, we report about Al/Ni and AlOx/NiOx MS fabricated by Ion Beam Deposition method using Ar and Kr plasma. All samples had 20 periods with thickness around 6.2 nm. The MS were studied by atomic force microscopy and X-ray reflectivity laboratory technique. The following structural parameters were achieved: surface roughness 0.4 nm for Al/Ni and 0.2 nm for AlOx/NiOx, as well as interdiffusion thickness 0.7 nm for Al/Ni and 0.25 nm for AlOx/NiOx. X-ray reflectivity of the first Bragg peak is 50% for Al/Ni and 43% for AlOx/NiOx at 8.048 keV (Cu K-alpha). The XSW experiment was done on Kurchatov Specialized Synchrotron Radiation Source (Phase beamline) in Moscow to compare XSW generation capabilities of structures. [1] E. Schneck, et. al., Proceedings of the National Academy of Sciences of the United States of America 9521-9526 (2016) 113

Resume : One of the most important challenges of our society consists in solving the thermal management problem, which strongly limits any further development in technologies such as data storage and energy harvesting. At this day, nanostructuration is one of the most successful strategies for reducing thermal conductivity: its success can be intuitively understood in terms of an enhanced phonons scattering from grain borders, which reduces their mean free path down to the one typical for a topologically disordered structure, resulting thus in a very low thermal conductivity. In order to get a better insight into the microscopic mechanisms behind the thermal conductivity reduction due to nanostructuration, we have investigated the phonon dynamics in two materials whose nano-crystalline and amorphous phases are of high technological interest: a Zr-based multi-component metallic alloy renowned for its excellent mechanical properties, and a doped GeTe thin film used as phase change memory material. By means of X-ray inelastic scattering we have been able to measure the acoustic phonons both in the nanostructured and amorphous phase, thus getting a microscopic understanding of the effects of nanostructuration on phonons, compared with the effect of the topological disorder.

Resume : Despite multiple research approaches to prevent bacterial colonization on surfaces, infections are still a major problem with high health care costs respectively. Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide, since they can enhance the successful implementation as advanced antibacterial surface coatings. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. It is proposed that both the abrasiveness and the surface oxygen species of ZnO nanoparticles promote the biocidal properties of ZnO. In this current work ZnO nanoparticles were prepared by two precipitation methods using zinc acetate dehydrate (Zn(CH3COO)22H2O), sodium hydroxide (NaOH) and polyvinylpyrrolidone (PVP) as a surfactant in the first one and zinc nitrate (Zn(NO3)2¬) and sodium hydroxide (NaOH) in the second. The engineered nanoparticles were characterized by Atomic Force Microscopy (AFM), x-ray diffraction (XRD) analysis and Transmission Electron Microscopy (TEM) to decide the differences between the NPs of the two different methods concerning the size distribution, the shape and the morphology of the particles. AFM revealed at both samples a unique nanoparticulate morphology, with average size diameter 60nm. The presence of ZnO was established via XRD measurements and TEM imaging provided a valuable tool for the nanoparticles’ morphology. After the successful fabrication of both methods, AFM revealed that the optimum morphology and size distribution of the fabricated nanoparticles were at the second one. TEM imaging further reinforced those results, via the morphology analysis. The nanoparticles were incorporated into polymer mats and matrices and the properties of these surfaces with or without the presence of nanoparticles were investigated via Nanoindentation measurements. The NPs from both methods are very promising alternatives as antimicrobial agents for antimicrobial surfaces. Acknowledgements: This work has been partially supported by the NANOCARDIO Project “Nanomedicine for Advanced Bioactive/mimetic materials for Cardiovascular Implants” and by NanoReg II

Resume : Multicomponent multilayer TiAlN/SiAlN thin films were deposited in Nitrogen and Argon atmosphere by magnetron sputtering from two TiAl and SiAl targets on set of various substrates: glass, silicon, high speed steel. Total coatings thickness varies in range 0.1÷1.5 µm and individual layer is expected to be from 4 to 20 nm. Basic morphological and elemental analysis was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). As advanced non-destructive analysis, various method of X-ray diffraction (XRD) were used. Calculation of bilayer thickness in thin films deposited of silicon substrates and evaluation of roughness were done using data of X-ray reflectivity (XRR) analysis. Results of measurements were also crosschecked with values obtained by SEM on cross-section samples. Initial phase identification was performed with conventional θ/2θ XRD patterns. To control X-ray beam penetration depth and to obtain information about phase evolution through the films depth profile the grazing incidence and in-plane XRD scanning were used. Appropriate lattice parameters, as well as crystalline size, were calculated. Residual stresses were evaluated from d-spacing vs sin2ψ plots. Considered techniques have demonstrated their advantages in analysis of multilayer samples.

Resume : BepiColombo is a mission planned by the European Space Agency (ESA) to reach Mercury, the least explored planet in our Solar System. The mission will face long-term exposure to high temperatures up to 350 deg. C, thermal cycling between extreme temperature values, and high levels of radiation. A new porous “Nanovation” coating (V14) was developed by Ceranovis in cooperation with ESA to deal with the harsh conditions. The coating comprises a sintered mixture of oxides/nitrides using a silicate binder deposited on a titanium substrate. Results of tests conducted by ESA will be presented. The coating’s structural integrity was followed using PXRD. Impact of sealing of the a priori porous coating with additional agents, batch variability, environmental testing and in situ thermal cycling were assessed.

Resume : All imperfections on the surface of coated tools have a strong influence on their tribological performance. In the running-in phase, the real sliding contact area is limited to the asperities, which tend to be cut off or fractured due to mechanical loading. The most common asperities on coated tools are nodular defects. During the operation of tools, different failures of tool's surface can be caused by cracks that initiate at coating defects. Particular problem are nodular defects, which collapse and form abrasive particles in the sliding contact area. High shear stresses cracks are also induced in the coating matrix. For these reasons the abrasive wear is very intensive during the run-in period. An imperfection on the surface of forming tool also represents a potential initial point for the beginning of galling and sticking of the workpiece material. All PVD hard coatings also contain some degree of microporosity; i.e., open pores, pinholes, void zones around the nodular defects or droplets, microcracks and pores between the columns. Such coating imperfections significantly reduce its protective nature in a corrosive media. In this work the processes that occur between the coating containing defetcs and a typical tribological counter body (Al2O3and 100Cr6) are analyzed. We will present the role of growth defects in the sputter deposited TiAlN coating during the running-in period of the ball-on-disk tests.

Resume : Among the candidates for the substitution of hard chromium, Ni-W alloys present attractive mechanical and tribological properties. These alloys are often obtained by electrodeposition, but nickel salts are harmful species for the environment and for the health. Magnetron sputtering could be an alternative method to deposit these alloys. Thus, the aim of this study is to compare the properties of Ni-W coatings deposited from both methods and particularly their corrosion resistance. The W content varied between 0 and 18 at.% for the electrodeposits and from pure Ni to pure W for the PVD coatings. Polarization curves and electrochemical impedance spectroscopy measurements were performed in acidic sulfuric solutions. Even if the same trend is followed regarding the influence of W, PVD coatings show a higher reactivity than electrodeposited coatings. A careful control of the metallurgical states of the coatings was performed to explain this behavior. The microstructure and the contamination of the coatings were characterized by using different techniques in order to evaluate grain size, crystallographic texture, nature of grain boundaries, morphological defects, impurities contents…The nature of the corrosion products was also investigated by using Raman and XPS spectroscopy. Results were then compared for both processing techniques in order to identify which metallurgical parameters are responsible for the higher reactivity of the PVD coatings in acidic solutions.

Resume : Diamond-like carbon (DLC) coatings have been widely used in many mechanical applications and attracted significant attention owing to their excellent properties including high hardness, low friction coefficient and high wear-resistance. This work presents a study of The influence of pure Ti, Nb or Cr adhesion interlayers on the tribological properties and impact wear resistance of Diamond like carbon (DLC) coatings deposited on high speed steel (M2) substrates using hybrid deposition process that combines radio frequency plasma enhanced chemical vapor deposition (RF PECVD) and magnetron sputtering in Ar, H2 and C2H2 gas mixture atmospheres. Impact-wear tests were used to study the interface deformation, contact failure and wear mechanisms. A 6 mm diameter steel 100Cr6 ball was used as the impacting body and the impact frequency was set at 10 Hz. After these tests, the wear craters were studied by 3D microscope, and non-contact profilometer. The structure was investigated by scanning electron microscopy. Chemical bonding was studied by Raman spectroscopy and X-ray photoelectron spectroscopy. The friction and wear behaviors were characterized using a ball-on-disk tribometer. Mechanical properties including residual stress, hardness, adhesion strength were evaluated by nanoindenter, scratch tester and surface profiler.

Resume : Superhydrophobic surfaces (SHSs) combine a tailored nanostructure with low surface energy to trap air between surface features, excluding liquids from penetration and hindering wetting. These surfaces have drawn huge interest since the liquid repellence involves additional relevant properties, from self-cleaning to anti-icing. Concerning the frictional drag reduction effect, which is hugely promising in maritime applications, further investigations are needed to identify the key parameters controlling the interaction between SHSs and turbulent flow. With this aim, the mechanism responsible for drag variation has been analyzed by means of a properly designed experiment in a high speed recirculating channel, where a double floating plate arrangement allows for drag evaluation on both a SHS and a reference smooth one. At same time, plastron monitoring is accomplished through a high speed camera. Aluminum plates bearing different water-repellent coatings are considered. The first SHSs typology is obtained by deposition of a nanostructured hybrid coating, made of 200 nm-long boehmite lamellae creating a flower-like nanostructure, and chemically grafted fluoroalkylsilane chains (Lotus leaf approach). The second one is realized according to the SLIPS approach, infusing a fluorinated lubricant oil within the pores of the hybrid coating. Insights into the plastron properties, their evolution with time and flow velocity and their efficacy at reducing frictional drag are here presented.

Resume : The deposition of DLC films is an effective way to protect elastomers under sliding contact. The presence of the DLC film minimizes the wear and avoids the strong interaction with the counterpart caused by the tackiness of the rubber. However, the frictional behavior of the ensemble is far from being obvious, and depends strongly on the testing/operation conditions. This is because the DLC-elastomer combination is a system where the overall frictional behavior depends not only on the surface interactions, but also on the mechanical properties of the substrate. For a critical review reference is made to [1]. In this contribution, we will show how the viscoelastic properties of the rubber have an extraordinary influence on the frictional behavior of the whole ensemble. We will review several experimental results that illustrate those effects, such as load or counterpart variations. The observed phenomena are explained using a combination of adhesive (i.e. interfacial contact) and hysteresis (i.e. substrate properties) contributions. The evolution of size and shape of the contact area is used to account for the frictional behavior beyond the first lap. The role of the velocity and frequency are explored as well through ‘ad-hoc’ modeling. Finally, as a consequence of the different phenomena explained, some remarks regarding the selection of the proper elastomer depending on the operation conditions are made. [1] D.Martinez-Martinez and J.Th.M. De Hosson, Surf. Coat. Technol. 258 (2014) 677–690.

Resume : Recently, we have showed that Zr–Cu thin-film alloys can be prepared as metallic glasses in a very wide composition range (30–65 at.% Cu) by non-reactive magnetron co-sputtering. In the present study, we focus on characterization of their properties and thermal behavior in more detail. In addition, we investigate the effect of an incorporation of Hf into the Zr–Cu thin-film metallic glasses on a potential improvement of their behavior. The films were deposited using three unbalanced magnetrons equipped with Zr, Hf and Cu targets in pure Ar. The magnetron with the Zr and Hf targets were operated in a dc regime while the Cu magnetron in a high-power impulse regime. The Zr, Hf and Cu contents in the films were controlled by adjusting the dc powers and the average target power in a period, respectively. The films were deposited without an external heating onto rotating substrates. Mechanical properties of the Zr–Cu thin-film metallic glasses are strongly dependent on the elemental composition. A gradual growth of hardness with increasing Cu content up to 70 at.% correlates well with an evolution of the glass transition temperature and the crystallization temperature. The Zr–Cu films prepared with the Cu content higher than 50 at.% or at a moderate substrate bias exhibit a tendency to be more resistant to the formation of shear bands during indentation. An incorporation of Hf improves the mechanical properties of the films and the thermal stability of their glassy state.

Resume : The electronic, optical, magnetic, and catalytic properties of nanoparticles depend on their geometry and material composition [1]. Applications in liquids and in particular water are, however, limited for a number of promising nanomaterials, as they are prone to corrosion [2,3]. Here, we present a method that can be used to protect complex hybrid 3D nanocolloids against corrosion. The method uses a nanoscale shadow growth technique, which we term ‘nano-glancing angle deposition (nanoGLAD)’ [4]. It can be used to grow three dimensional (3D) nanocolloids with some flexibility in the size, shape, and material composition of the nanoparticles. However, this scheme alone does not offer a means to prevent corrosion. Here, we show how the method can be adapted to grow 3D core-shell nanocolloids that are stable in various physiological environments [5]. We report a refined nanoGLAD scheme which, in conjunction with atomic layer deposition (ALD), can be used to protect multifunctional nanocolloids even in corrosive environments. The challenge is to ensure the complete encapsulation of the nanomaterial (core) by a defect-free shell layer. We discuss a promising metallic oxide shell layer that is chemically inert and that does not affect the colloidal stability. We demonstrate magnetic nanocolloids that without the protective layer corrode within hours in an acidic environment, but that are stable for weeks and in some cases even months when grown by the advanced nanoGLAD process. Entirely new applications are possible [6,7], including ones with Mg nanoparticles in aqueous solutions [8] and for biomedical applications at low pH [9]. [1] Y. Xia, Y. Xiong, B. Lim and S. E. Skrabalak, Angew Chem Int Ed, 2009, 48, 60-103. [2] A.-H. Lu, E. L. Salabas and F. Schüth, Angew Chem Int Ed, 2007, 46, 1222-1244. [3] A. M. Goodman, Y. Cao, C. Urban, O. Neumann, C. Ayala-Orozco, M. W. Knight, A. Joshi, P. Nordlander and N. J. Halas, ACS Nano, 2014, 8, 3222-3231. [4] A. G. Mark, J. G. Gibbs, T.-C. Lee and P. Fischer, Nat Mater, 2013, 12, 802-807. [5] H.-H. Jeong, M. Alarcón-Correa, A.G. Mark, K. Son, T.-C. Lee, and P. Fischer, Corrosion protection of nanoparticles (In preparation). [6] H.-H. Jeong, A. G. Mark, M. Alarcon-Correa, I. Kim, P. Oswald, T.-C. Lee and P. Fischer, Nat Commun, 2016, 7, 11331. [7] H.-H. Jeong, A. G. Mark, T.-C. Lee, M. Alarcón-Correa, S. Eslami, T. Qiu, J. G. Gibbs and P. Fischer, Nano Lett, 2016, 16, 4887-4894. [8] H.-H. Jeong, A. G. Mark and P. Fischer, Chem Commun, 2016, 52, 12179-12182. [9] D. Walker, B. T. Käsdorf, H.-H. Jeong, O. Lieleg and P. Fischer, Sci Adv, 2015, 1, e1500501.

Resume : Recent technological developments have led to the emergence of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) with oscillating, rotating, and sliding contacts. Thus, it’s fundamental to improve the tribological performance to reduce stiction, friction and wear. The use of ultrathin coatings can improve the performance of those systems. In this work WS2 thin films were deposited by DC and RF magnetron sputtering with decreasing thickness from 1000 to less than 8 nm. The coatings were characterized concerning its thickness, structure and tribological performance. The roughness Ra obtained by AFM, increases with the increase of the thickness with a nonlinear growth trend. The coatings with thicknesses higher than 250 nm present a surface morphology with valleys oriented in one direction related with the shadowing effect due to the rotation of the substrates. The films were analysed by TEM in plan view, the results allows to conclude that films grow in an initial stage uniformly with the basal planes (002) parallel to the surface. Then, the growth changes to a columnar morphology with the columns having the basal planes oriented perpendicular to the films surface. The films were tribologically tested, the results showing that thickness influences the friction performance, mainly in the running in period, changes explained by the difference in the morphology through film thickness.

Resume : Protective ceramic coating such as TiN, TiAlN, c-BN, etc. generally exhibit high hardness and stiffness which make them suitable for different applications. However, these coatings often suffer from brittleness and preparation of next-generation protective coatings with high hardness and moderate ductility is a current challenge in coating industry. In this regard, the ab-initio simulation have predicted that boron and carbon based coatings with a structure very similar to MAX phases can exhibit unusual combination of high stiffness and moderate ductility. In this study, the X-B-C (X=Mo and W) coatings with various compositions were deposited by co-sputtering of X, C and B4C targets at different substrate temperatures. Mid-frequency pulsed DC plasma excitation was employed to enhance the ion flux on the substrate and subsequently promote the crystallization of the coatings. The results indicate that the deposition conditions resulted in growth of partially crystalline Mo-B-C coatings with nanocomposite structure where small Mo2BC crystallites of ~ 10 nm size were embedded in an amorphous matrix. These coatings showed high hardness of 32± 1 GPa and extremely high fracture toughness. The high level of crack resistance in hard coatings observed for partially crystalline Mo-B-C coatings with nanocomposite structure is impossible to be met with commercially available coatings tested in a similar manner.

Resume : Of the large class of the biocompatible coatings, those consisting of carbonitride of transition metals have been shown to fulfil to a large extent the requirements demanded for insertion into biological environment. They provide solutions to the material biocompatibility problems experienced by implantable bearing metallic surfaces, being successful in increasing the service life of the orthopaedic implants. ZrTiCN and ZrNbCN coatings, selected because each metal easily forms hard carbides and nitrides, were investigated as possible candidates for biomedical applications. The coatings were deposited on Ti based alloys, by cathodic arc evaporation technique in reactive gas mixture of Ar+CH4, and characterized for elemental (EDS) and phase (XPS) compositions, crystalline structure (HR-XRD), surface topography (SEM, AFM), hardness (nonoindentation tests) and adhesion (scratch tests). Because high corrosion resistance in body fluids is crucial for an optimal performance of biomedical devices, in vitro corrosion resistance investigation of novel biomaterials represents a compulsory requirement. The corrosion behaviour and tribo-corrosion resistance of the coatings immersed in synthetic body fluids (SBFs) were assessed and discussed in corroboration with coatings' physico-chemical and mechanical characteristics. We acknowledge the support of the Romanian Research and Innovation Ministry, project PN-III-P2-2.1-PED-2016-1580.

Resume : The preparation of diamond thin films at low temperatures (T < 410 °C) enables a wide range of novel applications, e.g. deposition on flat panel displays, plastics, and other materials that don’t withstand high temperatures. The crucial requirement for diamond growth at low temperatures is a high plasma density at low gas pressure, leading to a low thermal load onto sensitive substrate materials. Such conditions are not within reach for resonance cavity plasma systems, which typically operate at pressures above 20 mbar. Linear antenna microwave delivery systems, however, allow depositions at pressures below 1 mbar [1]. Moreover, large area deposition is feasible over substrate diameters of 30 cm. Nevertheless, the use of linear antenna microwave plasma enhanced chemical vapour deposition systems, and in particular the growth of high quality diamond layers, remains understudied. In addition, for the development of nanocrystalline structures or devices, a bottom-up approach that allows control over the obtained morphology would be highly valuable. In this work the co-deposition of high quality plates and octahedral diamond grains in nanocrystalline films is reported. In contrast to previous reports claiming the need of high temperatures (T > 1000 °C) [2], low temperatures (320 °C ≤ T ≤ 410 °C) were sufficient to deposit diamond plate structures. Cross-sectional high resolution transmission electron microscopy studies show that these plates are terminated by large {111} surface facets. Moreover, the grain boundaries are shown to be quite sharp and clean, which means there is very little disorder in between the grains. The high diamond quality is confirmed by Raman and electron energy loss spectroscopy both showing very small sp2 contributions to their respective spectra. Up to now, literature reports have focused on the characterisation of these plates and multiple growth models have been proposed [3, 4]. These models start from an initial diamond structure that contains plenty of stacking faults, i.e. layers of so-called hexagonal diamond, and account for the development of plates by preferential growth sites or by the relative growth rates of crystal facets. Nevertheless, in none of the previous reports an explicit reason for the presence of these stacking faults is given. Optical emission spectroscopy can reveal the plasma characteristics responsible for the growth mechanisms behind this particular morphology. In this work a model is proposed that accounts for the initial development of these plates full of stacking faults and the growth of this morphology at low temperatures. References 1. N. Neykova, H. Kozak, M. Ledinsky, and A. Kromka, Vacuum, 86, 6, 603–607, 2012. 2. C.-A. Lu and L. Chang, Mater. Chem. Phys., 92, 1, 48–53, 2005. 3. J. C. Angus, M. Sunkara, S. R. Sahaida, and J. T. Glass., Journal of Materials Research, 7, 11, 3001–3009, 1992. 4. H.-G. Chen and L. Chang., Journal of Materials Research, 20, 03, 703–711, 2005.

Resume : The copper-oxygen binary system contains three oxides (Cu2O, Cu4O3 and CuO) that are suitable for energy applications: electrodes in Li-ion batteries, absorbent layer in solar cells, p-type transparent conductive oxide… The reactive sputtering is a powerful method to synthesize these three materials as pure phases or as mixtures. Recently, the local epitaxial growth (LEG) has been evidenced in Cu2O thin films [1]. The conditions to extend the LEG to other phases such as Cu4O3 or NiO will be discussed. Finally, the consequence of the local epitaxial growth on the microstructure of biphased copper oxide thin films will be explained. Within a given oxygen flow rate range, it is possible to grow self-assembled vertically aligned columnar Cu2O+Cu4O3 nanocomposite thin films on glass and silicon substrates at room temperature. Microstructure analyses show that each phase in nanocomposite films has the columnar growth along the whole thickness, while each column exhibits the single phase characteristics. The LEG of Cu2O is responsible for such an unusual microstructure. The intermediate oxygen flow rate between those required to synthesize single phase Cu2O and Cu4O3 films produces some Cu2O nuclei, and then the local epitaxial growth provides a strong driving force to promote Cu2O nuclei to grow sequentially, giving rise to Cu2O columns along the whole thickness. Low resistivity has been observed in such kind of nanocomposite thin films [1] Y. Wang et al., Acta Mater. 76 (2014) 207

Resume : We describe a new versatile route to integrate functional micro-mesoporous materials (sol-gel materials, Metal-Organic Frameworks -MOF-) into 2D photonic devices (Diffraction Gratings). The goal is to combine the original properties of micro-mesoporous materials (high porosity, sorption selectivity) and of the periodic structures (light confinement, diffraction) to achieve optical transduction for smartphone-assisted sensing of toxic vapors. A new technique called Degassing Assisted Patterning is used for the direct nano-imprinting of sol-gel thin films (SiO2, TiO2) or MOF nanoparticles, on both rigid and flexible transparent substrates. Our sensing approach relies on the monitoring of the diffracted luminosity that is directly correlated to the amount of toxic compound (alcohols, aromatic hydrocarbons…) in the atmosphere. Probing is performed by a simple smartphone or CCD camera without need of complex optical instrumentation. Unlike conventional photonic devices (mainly colorimetric), this specific configuration allows spectroscopic-like measurements. We show that sol-gel based porous homo- and hetero-structures can be fabricated and used as responsive diffraction gratings. In order to improve the selectivity towards the targeted gas, MOF nanoparticles were coupled to the sol-gel photonic device and selective detection of toxic styrene vapors was demonstrated for the first time with ZIF-8 materials at concentration as small as 58 ppm (below the permissible exposure limit).

Resume : Recently, the researchers’ efforts in vibration energy harvesting have focused on the development of reliable techniques of fabrication of thin-layer piezoelectric structures on flexible support. Thin films of lead zirconate titanate (PZT) have been prepared using chemical deposition on a flexible metallic substrate: a commercial aluminium (Al) foil with thickness less than 30 µm [1]. This way of fabrication is cheap and the lightness of the micro-generator makes it sensitive to air flow. To obtain high electrical energy density, the interdigitated electrodes (IDE) structure is a more efficient design than the parallel plate electrodes (PPE) and also present the advantage to operate in piezoelectric 33 mode with larger piezoelectric coefficients than in 31 mode. To realize this structure, PZT films must be separated from the aluminium ground plane before the realization of IDE. However, PZT thin films are not rigid enough to stand alone so a new substrate has to be used with a good flexibility and insulating properties. Specific polymer materials like some thermoplastics are good candidates for the new insulating and flexible substrate because of their natural flexibility. The major drawback with these soft polymers is their low resistance against thermal treatment which does not allow the direct synthesis of PZT onto polymeric substrate. The proposed solution is the transfer of the PZT thin film, obtained by classic methods, onto the polymeric substrate. This solution was used by Park et al. [2] to realize PZT on polymer, but the employed method - laser lift-off - is expensive and could be hard to transfer to the industry. In this context, a new procedure for the realization of piezoelectric PZT thin film on a polymer substrate has been developed. Starting from the PZT/Al thin film created in the laboratory, a chemical process is used to transfer the piezoelectric material to a polymer substrate. This process is cheap and would be easily transferred to the industry. In addition, with this chemical method, the metallic substrate is removed from the complete surface (~ 6 cm2) of PZT thin film in one step while the laser lift-off method requires several steps to separate PZT from the first substrate. Thus, this paper will describe the method of realization of the flexible PZT thin film on a polymer substrate. The structural (SEM, XRD, EDX) and ferroelectric characterizations of the PZT/polymer thin film carried out to check the good quality of the transferred PZT thin film will also be presented. References [1] R. Seveno and D. Averty, J. Sol-Gel Sci. Technol. 68, 175 (2013). [2] K.-I. Park, et al. Adv. Mater. 26, 2514 (2014).

Resume : Copper or copper alloys have peculiar properties which make them suitable for a wide range of applications. In this work static and dynamic superhydrophobicity on Cu surface was achieved through a nano-engineering approach with deposition of organic/inorganic coatings made up of alumina nanoparticles - obtained by sol-gel routes - grafted by a fluoropolymer moiety. The selected processing conditions, able to control the reactivity of Cu itself, led to the formation of an homogeneous coating with a peculiar flower-like morphology, responsible for the advanced water repellence. The role of inorganic layer clearly came out since the chemical modification induced by the fluorine-rich molecule alone was not able to provide such advanced properties. Extensive SEM and XPS analyses allowed to locate the key features of the coated surfaces in the light of the most suitable annealing cycles. Heat treatments at 200 and 300°C ensured the formation of the proper morphology, while, when the temperature raises up to 400°C, CuO microwires, deleterious to superhydrophobicity, were detected. Durability tests kept unchanged the Cu performances even when low annealing temperature is concerned.

Resume : Nanoparticles of noble metals are having great attention due to their unique response to visible and infrared radiation where their surface plasmon resonance (SPR) becomes active to enhance the optical absorption. In this work the results of obtaining TiO2/Ag films by combining the techniques of laser ablation of solids in liquids (LASL) and electrophoretic deposition in the same process are presented. Titanium oxide nanoparticles are synthetized by ablating Ti plate submerged in water while an electric field is used to deposit the nanoparticles on a conducting polymer used as electrode. The same process is repeated to ablate a silver target and deposit Ag nanoparticle on the same substrate to obtain a uniform film of TiO2/Ag. The composition, topography, crystalline structure of titanium oxide and silver nanoparticles have been studied by energy dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), X ray diffraction (XRD). UV-visible spectrometry is used to estimate the band gap of the titania colloidal solution as well as to check the optical properties of the final film. The obtained films consisted of porous coatings composed of titania and silver nanoparticles ranging from several to 60 nm and showing shift toward higher wavelengths when compared with titania films.

Resume : Diamond-like carbon (DLC) coatings are most often used successfully in a broad range of machinery applications due to their ability to improve the mechanical and chemical resistance of surfaces exposed to wear. Quite a few attempts were made to achieve similar effects in load-bearing implants such as hip, knee and spinal disc prostheses. However, several clinical studies using DLC coatings on articulating joints showed severe problems due to partial coating delamination after several years in vivo [1], which had dramatic effects for the affected patients. Such observations obviously affected the use of DLC in the MedTech field. This talk presents an overview of the main known failure mechanisms of DLC-coated medical alloys and their impact on the lifetime of the coated implant. Based on these mechanisms and using long-term tests an accurate description of the damaging processes was developed, which provides an instrument to predict the in vivo survival time and especially the long-term adhesion stability of the coating. The formation of a few atomic layers of a reactively formed interface compound, usually metal carbides, proved to be essential for reliable adhesion. Furthermore, contaminations from residual gas or any cross contamination, as they occur in standard DLC deposition processes, will result in different reactively formed interface materials with different properties. This was shown for several adhesion-promoting interlayer materials, whose sensitivity towards oxygen contamination and the corresponding impact on adhesion performance was investigated. The most promising interlayer candidate was tested in a spinal disc simulator in simulated body fluid; this interface-film optimized coating remained stable over an articulating period that corresponds to 100 years of articulation [2]. Rockwell-indentation based corrosion tests indicate a corrosion resistance of the interfaces of up to 60 years in vivo. REFERENCES: [1] R. Hauert, K. Thorwarth, G. Thorwarth, "An overview on diamond-like carbon coatings in medical applications", Surface and Coatings Technology 233, pp 119-130, year 2013. [2] K. Thorwarth, G. Thorwarth, G. R. Figi, B. Weisse, M. Stiefel, R. Hauert, “On interlayer stability and highcycle simulator performance of diamond-like carbon layers for articulating joint replacements”, International Journal of Molecular Sciences, 15(6), pp 10527-10540, year 2014.

Resume : Carbon materials have prompted great interest in the biomedical field due to their good performance as coating for prosthetics and medical devices. However to realize their potential it is critical to control formation and composition of the protein corona in biological media. Localized Surface Plasma Resonance (LSPR) has emerged as a powerful technique for studying the thermodynamics and the kinetics of these biological interfacial events. In this report we discuss in situ protein adsorption studies carried out at different types of carbon thin films using a recently developed LSPR sensing method. The thickness of protein layers at carbon surfaces has been calculated from experimental plasmon shifts using finite difference time domain (FDTD) simulations. These results suggest that LSPR in combination with FDTD analysis are well suited to investigating and comparing protein adsorption at carbons, even in the case of carbon materials with highly dissimilar dielectric properties. Finally, the effect of glycoside modification at carbon films in reduction protein fouling were studied using a combination of in situ and ex situ techniques.

Resume : There have been enormous strides in the development of novel metallic biomedical materials over the past three decades. There is a wide range of application of metals used in the human body. They are used as a hip knee replacements, as arterial stents and surgical plates, screws, wires and surgical instruments. Whatever be their end use, all common metals tend to react with their environments to different extents and different rates. Wear and corrosion are ubiquitous problems that affect virtually every type of surface, especially those that come in contact with other surfaces. Tribological and corrosion resistant coatings are applied in various fields of science and industry. For medical application they should withstand corrosive body fluids environment, as well as guaranty the adequate wear resistant properties. The main goal of the work was the bio- corrosion and bio- tribological properties increase together with aesthetic impression improvement of metallic surfaces by application of advanced zirconium based Zr/ZrN DLC multilayer as well as Zr-Mg-Ag(Pt) nano- composites coatings. Coatings were deposited by the use of the magnetron sputtering technique. In the frame of the work multidisciplinary coatings characterization was performed. The characterization indicated the optimum bio- tribological coating for medical tools and metallic implants application. Acknowledgment: This work was supported by the National Science Centre No: 2015/19/B/ST8/00942 and National Center of Research and Development No: DZP/M-ERA.NET-2015/285/2016

Resume : Atomic layer deposition (ALD) is a thin film technology that in the past two decades rapidly developed from a niche technology to an established method. It proved to be a key technology for the synthesis of ultrathin film, the surface modification and the fabrication of complex nanostructured materials as well as the membrane tuning. [1] In this work, we will give an overview about our activities on ALD, from the design of nanomaterials to membrane applications. After a short introduction to ALD, the versatility of the technique for the fabrication of novel nanolaminates thin films [2] and functional nanomaterials [3, 4] will be showed. Selected examples, focused on its use for the engineering of nanostructured functional materials and membranes targeting applications in water purification, biofuel cells, osmotic energy, gas separation, and health [5-8] will be discussed. [1] Advanced Materials, 2012, 24, 1017 [2] J. Phys. Chem. C, 2016, 120, 5124–5132 [3] Nano Energy 1 (2012) 696 [4] Nanoscale 7 (2015) 5794 [5] Journal of Materials Chemistry A, 2016, 4, 6487-6494 [6] Journal of Materials Chemistry A, 2016,4, 17686-17693 [7] Biosensors and Bioelectronics, 2016, BIOS-D-16-01673R1 [8] Journal of Materials Chemistry A, 2014, 2 (48), 20650 – 20658

Resume : The ideal surface modification, in form of coating, on biomaterial for orthopedic implant applications is one that exhibits excellent biocompatibility with no adverse cytotoxicity, excellent corrosion resistance, and a good combination of mechanical properties such as high strength and good fatigue resistance, low elastic modulus and good wear resistance. Sputtering techniques are extremely versatile to produce nanostructured, homogeneous, dense, compacts and crack-free coatings. This technique offers multiple possibilities in the in-situ design of complex (near) pure beta-Ti textured coatings, with body centered cubic phase (bcc), free of toxic elements. Beta-rich Ti-Nb-Zr coatings allow the combination of three different phases (alfa, alfa” and beta), depending on the concentrations of Nb and Zr, which offer the best mechanical properties a priori. The focus of this work is to design ternary coatings and their nano-mechanical characterization. Results regarding grain size, texture and residual stress magnitude of Ti-22Nb-XZr (X=10, 20, 25 w.%) as a function of conditions, will be shown. Of particular interest is the evolution of hardness, Young’s modulus and residual stress values along the thickness, manifested by Ti-22Nb-XZr, as a function of bias voltage on the substrate. It is worth highlighting how initially the young’s modulus descends from 62.86 GPa, at 0 volts, to 46.97 GPa, at -63 volts, and then progressively increases to 89.15 GPa, at -148 volts. Magnitude of residual stress will be correlated with the concentration of beta and alfa” phases, showing how the increasing bias voltage facilitates the transformation from beta to alfa”, changing compressive residual stresses magnitude from -700 MPa, at -63 volts, to -100 MPa, at -148 volts. Furthermore, it will be show as the evolution of these mechanical properties are fundamentals in the design of coatings with high fracture toughness and high wear behavior.

Resume : Through evolution, nature has developed composite materials (e.g. bone, wood or nacre) with complex and hierarchical organization from the nano- to the macro-scale via molecular assembly. Such materials possess fascinating combinations of properties such as lightweight, strength or shock resistance by assembling hard and soft elements. Their remarkable mechanical performance at the macroscopic scale is the consequence of their hierarchical structure and the specific design at each level of organization. Among all methods available for the preparation of multifunctional nanostructured composite materials, the Layer-by-Layer technique is currently one of the most widely used due to its simplicity and versatility in combining a plethora of available nano-objects and macromolecules into finely tuned multifunctional architectures with nanometer scale control. Recently, we prepared transparent wood-inspired LbL nano-composite materials with mechanical properties challenging even medium quality steel (tensile strength around 500 MPa). The talk will illustrate some of our recent results on the design of nanostructured thin films prepared by combining hard nano-reinforcing anisotropic elements like nanofibrillated cellulose with soft polymer building blocks. Formation and growth of the different LbL-composites will be presented and their mechanical/optical properties will be discussed as a function of structure, composition, nano-object alignment and preparation conditions.

Resume : To make nanophase coatings based on metallic nanoparticles (NP) playing a key role in health and energy applications, one has to be able to: 1) tailor the NP properties (size, purity, crystallinity); 2) obtaining the coating directly on surfaces (type of surface, NP density); 3) understanding the coating properties (adhesion, mechanical behavior). Wet synthesis routes face the needs of colloidal stabilizers, the presence of impurities, the solvents and synthesis process costs. A flexible alternative synthesis route is the supersonic cluster beam deposition (SCBD), based on NP beams in gas phase environment. Here we show that Ag NP coatings can be deposited directly on glass or sapphire substrates via SCBD at room temperature and with a wide range of thicknesses, describing the NPs physical properties, the coating mechanical [1] and microbicidal behavior [2]. The coatings are composed of crystalline NP – with a bimodal size distribution at 6 nm and 1 nm diameter – and inter-NPs voids, the filling factor being 0.8, independently on the substrate type. The film’s density and sound velocity are 80% that of polycrystalline bulk Ag, whereas the elastic stiffness constants amount to only 50% with respect to the Ag bulk. The Ag NP coatings exert an effective and broad-spectrum bactericidal activity, both for reference strains and for a collection of clinical drug-resistant strains. [1] S. Peli et al. J. Phys. Chem. C 120 (2016) 4673 [2] E. Cavaliere et al. Nanomedicine 11 (2015) 1417

Resume : The technological impact of combining substrates technologies as growing platforms with the properties of functional advanced oxides is colossal given its relevant role in the development of novel and more efficient devices. However the precise control of interfaces and crystallization mechanisms at the nanoscale of dissimilar materials need to be further developed. As an example, the integration of high quality epitaxial oxide films and nanostructures on silicon as hybrid structures rest extremely challenging because these materials are structurally and thermally different. In this light, this work describes promising strategies used to accommodate advanced oxide nanostructures and thin films on silicon substrate via chemical solution deposition approach. Divers examples will be presented separated in two different approaches i.e: (i) oxide materials entirely performed by soft chemistry, such as nanostructured piezoelectric quartz thin films on silicon [1] or ferroelectric oxide nanowires thin films epitaxially grown on silicon [2], and (ii) complex oxide materials performed by combining soft chemistry and physical techniques, such as epitaxial active perovskite oxide nanostructured thin films on silicon using the combination of soft chemistry and MBE [3,4]. As a conclusion, this presentation will cover cutting-edge strategies based on the potential of combining epitaxial growth and chemical solution deposition to develop functional oxide nanomaterials on silicon with novel structures and improved physical properties. [1] Soft chemistry based routes to epitaxial A-quartz thin films with tunables textures A.Carretero-Genevrier, M.Gich, L.Picas, J.Gazquez, , D.Grosso, C.Boissiere, J.Rodriguez-Carvajal, and Clement Sanchez. Science. Vol 340. Pp 827-831 (2013) [2] Direct Monolithic Integration of Vertical Single Crystalline Octahedral Molecular Sieve Nanowires on Silicon. A. Carretero-Genevrier, J. Oro-Sole, J. Gazquez, C. Magen, L. Miranda, T. Puig, X. Obradors, E. Ferain, C. Sanchez, J. Rodriguez-Carvajal, N. Mestres. Chemistry of Materials 26 1019 (2014) [3] Integration of functional complex oxide nanomaterials on silicon J. Vila-Fungueirio, R. Bachelet, G. Saint-Girons, M. Gendry, M. Gich, J. Gazquez, E. Ferain, F. Rivadulla, J. Rodriguez-Carvajal, N. Mestres, A. Carretero-Genevrier Frontiers in Physics 3, 38 (2015) [4] Development of Epitaxial Oxide Ceramics Nanomaterials Based on Chemical Strategies on Semiconductor Platforms A Carretero‐Genevrier et al. - Advanced Ceramic Materials, (2016)

Resume : We propose a method for the elaboration, in a single step and in a confined chamber, of composite coatings made of nanoparticles embedded in a matrix. The process combines a beam of nanoparticles with Physical Vapor Deposition. The association of the two techniques is made possible by routing nanoparticles by aerodynamic means to the substrate, either immediately after their synthesis in the gas phase, or from atomized colloidal suspensions. The simultaneous deposition of the particles and the matrix is performed on the same substrate. The process allows a virtually unlimited selection in the respective chemical compositions of nanoparticles and the matrix, and a moderate temperature of the substrate. Different source types of nanoparticles are possible. A laser-driven pyrolysis reactor can be used for the in-situ synthesis. Laser pyrolysis is an efficient method to synthesize various high purity nanopowders, oxides and non-oxides, in a gas phase bottom-up approach. An atomizer that produces an aerosol from colloidal suspensions of previously synthesized nanoparticles can alternatively be used. The particle stream is formed by means of an aerodynamic lens system. This system is currently used to produce a collimated beam of particles under vacuum for further gas phase characterization or for precision 3D micro printing. It allows for long-term stable and high transmission of particles in a wide range of size and density. We show that it is possible to get an angle-controlled divergent beam of nanoaerosols by optimizing the geometry of a classical lens. In this way, homogenous deposition of nanoparticles is performed on large areas. We demonstrate the adaptation if the technique with pressure environment required for running a classical magnetron sputtering device. The later is used for depositing the material constituting the matrix of the composite film. The deposition of a large variety of materials is conceivable by this means. The possibility to elaborate large and homogenous nanostructured films were investigated with different types of nanoaerosols with different sizes and densities. Numerous application domains are already considered for this kind of nanostructured coatings, including photovoltaic, photocatalysis, aesthetic coatings, hard covering, biomedical and self-healing films. The development of the process is carried out in the frame of the HYMALAYAN project funded by the French Research National Agency (ANR) under Grant No ANR-14-CE07-0036. It is open to new potential applications.

Resume : In the present study, inclined, zigzag and spiral TiAg and TiCu thin films were GLAD co-sputtered using two different targets, both with an opposite and oblique particle incidence angle α of 80°. The first part of this work consisted on the optimization of the sputtering pressure (varied from 0.2 to 1.5 Pa) and resulting column angle (0° ≤ β ≤ 40°), using a simple pure Ti thin film system. Afterwards, using the selected sputtering pressure (0.25 Pa), both TiAg and TiCu systems were co-sputtered with inversely changed Ti and (Ag or Cu) target currents, in order to control the obtained Ti/Ag and Ti/Cu elemental concentrations. The elaborated coatings were characterized in terms of their composition, morphology, microstructure and electrical properties. Main results show that bi-component columns can be obtained in the inclined and zigzag architectures. However, significant morphological differences are visible depending on the orientation of the sample in relation to both targets. On the other hand, rather uniform structures are achieved in the spiral nanostructures. These differences translate into interesting electrical resistivity behaviours, with higher TCR’s (1.1×10-3 and 3×10-4 °C-1 for TiCu and TiAg, respectively) obtained in the spiral structures and increased orthogonal anisotropy (Aeff = 3 and 1.4 for TiCu and TiAg, respectively) in the inclined and zigzag architectures. Keywords: TiAg, TiCu, GLAD co-sputtering, composition, electrical resistivity, anisotropy.

Resume : The oblique angle configuration has recently emerged as an invaluable tool for the deposition of porous thin films by vacuum and plasma-assisted PVD techniques. In this presentation, an up to date description of its fundamentals and nanostructuration possibilities are given, along with numerous potential applications when these films are incorporated into functional devices. Overall, the large specific surface of the layers, associated to the existence of large open micro- and mesopores, make them ideal candidates whenever an interaction with a gaseous or liquid medium is required. Applications in sensor devices, e.g. of cholesterol or glucose, or in biomedicine, where the film surface energy can be tailored to allow the growth of living cells while inhibiting bacterial proliferation, will be envisioned. Moreover, applications in optofluidics, where the optical response of multilayered structures (photonic crystals) may be tuned when different liquids pass through the porous channels, will be displayed. Results will be presented based on, but not limited to, the activities of the Nanotecnology on Surfaces research group, involving computer simulations, fundamental experiments aimed at tailoring the film porosity as well as the development of laboratory-size functional devices targeting specific applications.

Resume : The growing need of an early detection of diseases is driving the scientific community to find innovative and cheap DNA sensors for diagnostics. To this purpose, device miniaturization and integration in control circuitries are needed for mass production, cost reduction, and to allow the device use to non-trained people. Silicon is the most suitable substrate to be used thanks to its cheap manufacturing and high-level integration. SiO2 surfaces are used for biomolecule immobilization on Si-based sensors. Unfortunately, SiO2 suffers contamination issues in saline solution; hence, if an “active” surface is needed, e.g. for electrical transduction, SiO2 is not the best choice. Our choice was to use silicon nitride, since it is a shield to the salts ions for the electrical device under it. We developed an optimized grafting protocol on pyrolytic Si3N4 surfaces and performed an exhaustive study after each immobilization step. The surface was characterized using contact angle, ellipsometry, Atomic Force Microscopy, and Transmission Electron Microscopy. A comparison with thermally grown SiO2 surfaces chemically treated with the same immobilization protocol was also performed. DNA detections, both electrical and optical, were carried out by measuring the sensing performances of opportunely fabricated devices, DNA-microarrays and MIS-like diodes, for optical and electrical detection, respectively.

Resume : Thin film metallic glasses (TFMG) have recently emerged as alternative film materials for many applications, such as micro-electro-mechanical systems and biomedical use [1]. Zr-based TFMG could for example combine promising antibacterial activity and high durability to be used as coating of medical instruments to prevent hospital acquired-infections. In this way, we recently characterized a silver-rich ternary Zr-Cu-Ag TFMG [2]. Its high antibacterial activity was clearly established but some development are needed to improve its corrosion resistance. In the present study, properties optimization of micrometer-thick Zr-Cu-(Ag) TFMGs, deposited by PVD magnetron sputtering for a wide Ag-content range [0-15 at.%] using a dual-target, was investigated. The thermal stability as well as structural, microstructural, mechanical, and electrochemical properties were characterized. These films are amorphous, smooth and display high hardness and an interesting passive behavior. Finally, the antibacterial activity of these TFMGs against E. coli and S. aureus were evaluated and correlated to the composition. [1] J.P. Chu et al., Thin Film metallic glasses: Unique properties and potential applications, Thin Solid Films 520 (2012) 509-5122. [2] A. Etiemble et al., Innovative Zr-Cu-Ag thin film metallic glass deposited by PVD magnetron sputtering for antibacterial applications, J. Alloys and Comp. (2016) doi: 10.1016/j.jallcom.2016.12.259.

Resume : The aim of the paper is to obtain active coatings made of silver doped hydroxyapatite with improved features on Ti6Al4V by pulsed electrochemical deposition in a single step (PED). The deposition was carried-out in a three electrode set-up as follow: Ti6Al4V – working electrode, Pt foil – counter electrode and SCE - reference electrode. The electrolyte was prepared by dissolving Ca(NO3), (NH4H2PO4) and Ag(NO3) in ultra-pure water. The deposition was performed with a potentiostat/galvanostat by pulsing the potential as follows: a potential (EON) of -2 V was applied for a period of time (tON), followed by a breaktime (tOFF) with an applied potential (EOFF) of 0V. The obtained coatings were analyzed in terms of morphology, elemental and phase composition. In order to evaluate the electrochemical behavior of the obtained coatings, electrochemical measurements have been performed in simulated body fluid (SBF) at 37 °C and pH of 7.4, in order to mimic the human body environment. The silver doped HAp active coatings were successfully achieved and confirmed by SEM-EDS and XRD analysis. Also the electrochemical investigations have confirmed that the coated samples present an improved resistance to corrosion when compared to the uncoated ones. It can be concluded that PED is an effective method for preparing Ag doped HAp coatings with balanced bioactive and antibacterial properties.

Resume : Wide band gap oxides grown by Atomic Layer Deposition (ALD) method (ZnO, Al2O3, TiO2, HfO2, ZrO2) show antimicrobal activity. For the experiments we used disk diffusion method, normally used to determine drug sensitivity. Paper disks coated with thin oxide layers were tested on substrates plated with bacterial suspensions (0.5 by McFarland). Bacteria selected for experiments were chosen from reference strains and strains commonly present in hospi-tals. The highest efficiency of anti-microbal action was observed for HfO2 and ZrO2, and the lowest for TiO2. The key aspect of our method is that ALD allows coating of temperature sen-sitive materials as well as medical equipment and instruments in hospitals, dentistry and in a food industry. Thus, coating with high-k oxides, showing anti-bacterial activity, can be used in range of potential applications in medicine, veterinary, health care and food industry. This work was partially supported by the National Science Center (Decision Nos. DEC-2012/06/A/ST7/00398 and SGGW DEC-2012/05/E/NZ4/02994, 20/0139/N/ST3/04189.

Resume : Bacteria formation and colonization on biomedical interfaces can cause several adverse events, from hampering the wound healing process to cause the rejection of a medical implant. In case of metallic implants, several surface modification solutions have been extensively studied as the surface immobilization of biomolecules to control the adsorption of proteins and adhesion of cells and bacteria. Aiming at more sustainable green methodologies for surface biofuntionalization, in this communication an original, fast, solvent free and dynamic deposition process will be presented. Based on atmospheric pressure plasma dielectric barrier discharge (AP DBD) process, methacrylic-based interlayers containing highly chemically reactive quinone groups were deposited on metallic surfaces and further exploited for the covalent immobilization of bioactive enzymes. The functional layers were produced at high deposition rates, with thickness ranging from several nanometers to few microns. In addition to surface chemical and morphological characterizations, the stability of the layers was assessed through immersion tests in buffer media from pH 6 to 8. As a case study, Dispersin B, an enzyme with anti-biofilm properties, was grafted in a single step. The excellent anti-biofilm activity against staphylococcus epidermidis biofilm forming and osteoblast cells viability were found comparable to the polydopamine-based layers prepared by wet chemical methods with slow deposition rates.

Resume : Polyelectrolyte multilayers constitute a prototype of polymeric films built by a step-by-step process. They are obtained by the alternate deposition of polyanions and polycations on solid substrates: each layer of polymer adds to the oppositely charged surface thanks to electrostatic forces, more precisely charge overcompensation (1). The buildup process appears to be extremely versatile and can be used with almost any kind of polyanion/polycation pair on almost any kind of substrate (2,3). The step-by-step technique has also been extended to other types of interactions besides electrostatic interactions between the two interacting polymers: polymer multilayers whose cohesion is based on hydrogen bonding were for example reported. In order to render multilayers mechanically more robust, multilayers based on covalent bonds between the different polymers were also developed. Covalent bonds were obtained either by first building up multilayers based on non-covalent bonds (electrostatic, hydrogen bonding...) and later by adding a cross-linking step to the film or by anchoring each polymer layer directly through covalent bonds onto the previously deposited one. This later buildup strategy is known in the literature as "covalent layer-by-layer assembly". Whereas the general laws governing the buildup of polyelectrolyte multilayers have been established (linear vs exponential growth, effect of the ionic strength on the buildup process…) only very few studies trying to establish the laws governing covalent layer-by-layer assembly have been reported so far. Here we report a study investigating the covalent layer-by-layer assembly of thin nanogel films by alternate deposition of bi- and/or tetra-functional poly(ethylene glycol) (PEG) chains bearing thiol with other chains bearing maleimide terminal groups. At the macroscopic scale, mixing PEG having maleimide terminal functions with PEG having thiol terminal functions have been demonstrated to form cross-linked biocompatible hydrogels (4). The possibility of a step- by-step buildup process to form a “nanogel” with these molecules is by far not obvious. Indeed, whereas in the case of the alternation of polyanions and polycations, electrostatic interactions can take place all along the polyelectrolyte chains, covalent bond formation requires close proximity of the two interacting groups and is thus much more restricted along the polymeric chains. On the other hand, only few interactions per chain already allows for a film construction based on covalent interactions while numerous electrostatic interactions are required for the film to be cohesive. Our goal is to investigate some rules governing the buildup of such nanogel films, their possibility to be built on different types of substrates and also to assess their capacity to be functionalized with biomolecules such as the ligand/receptor couple biotine/streptavidine. Different buildup processes resulting in the variation of several parameters as for example the length of the chains or the type of anchoring layer, have been studied using a dissipation enhanced Quartz Crystal Microbalance (QCM-D) system. (1) Decher,G.;Hong.J.D; Schmitt,J., Buildup of ultrathin multilayer films by a self-assembly process : III.. Consecutively alternating adsorption of anionic and cationic polyelectolytes on charged surfaces ,Thin Solid films, 1992, 210-211, 831-835 (2) Rios,C; Longo.J; Zahouani.S et al, A new biomimetic route to engineer enzymatically active mechano-responsive materials, Chemical Communications, 2015,51,5622-5625 (3) Zahouani, S.; Chaumont, A.; Senger, B.et al, Stretch-induced helical conformations in Poly(L-lysine)/Hyaluronic Acid multilayers, ACS Applied Materials and Interfaces,2016,8,14958-14965 (4) Yu.J; Xu.X; Yao.F et al, In situ covalently cross-linked PEG hydrogel for ocular drug delivery applications, International Journal of Pharmaceutics, 2014,470,151-157

Resume : Hematite (α-Fe2O3) is an antiferromagnetic material at room temperature, which presents a wide interest in diverse applications due to its low toxicity, abundance and easy control of morphology. Specifically, this iron oxide phase is a promising semiconductor for gas sensor and photocatalytic applications because its band gap is about 2.1 eV (in the range of the visible spectrum). However, the efficiency of bulk α-Fe2O3 is limited due to its low hole mobility and short carrier lifetimes. Nowadays, increasing efforts are done to tailor the physical and chemical properties of α-Fe2O3 thin films. Between the different approaches to control the final properties and improve the reactive response, the variation of thickness of the α-Fe2O3 films and using different growing substrates in terms of atomic and crystalline structure as well as the growth process is a promising option. However, it is necessary to create more insight in the mechanism that define the physical and chemical properties. The influence of the charge carriers at the interface between the thin film and the substrate is crucial but the crystallinity, morphology and the film orientation as well. In this work, we evaluate the growth factors of α-Fe2O3 single crystalline thin films deposited by Pulsed Laser Deposition (PLD) on three different substrates: STO (111), α-Al2O3 (0001) and LaAlO3 (001). An exhaustive study of morphological and structural properties of thin films and the possible formation of other phases at the film/substrate interface has been carried out. For that, several techniques has been employed: Grazing Incidence Surface X-Ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Spectroscopy (XAS), Atomic Force Microscopy (AFM) and Raman Spectroscopy. Moreover, we present preliminary results about the efficiency of these α-Fe2O3 thin films as gas sensor for CO and CH4 gas from the conductance measurements, which are correlated with their morphological and structural properties.

Resume : Carbon materials are widely used in medical applications in the form of nanodiamonds, carbon dots, carbon nanotubes and diamond like carbons. The excellent performance of carbon-based biomaterials is attributed in part to the unique and desired physico-chemical properties of these materials. However, the origin of their desirable bioresponse is not yet fully understood and there is currently great interest in understanding what role carbon surface chemistry might play in determining the great performance of carbon as a biomaterial. In this work we present a detailed study of the physico-chemical properties of disordered carbon and carbon-modified thin films. A combination of spectroscopic and microscopic techniques was used to characterise carbon thin films composition, topography, surface charge density, wettability and surface free energy. X-ray photoelectron spectroscopy (XPS), contact angle, atomic force microscopy (AFM), ellipsometry and surface zeta potential methods were utilised to characterise four types of disordered carbon surfaces: amorphous carbon (a-C), hydrogen doped amorphous carbon (a-C:H), oxidised amorphous carbon (a-C:O) and carbohydrate-modified amorphous carbon (a-C:Lac). The four disordered carbon surfaces were further incubated in biological media and a relation between carbon surface chemistry, wettability and charge density and carbon bioresponse was established.

Resume : A composite material is a heterogeneous material which consists of clearly distinguishable phases, often referred to as the reinforcement and the matrix. The purpose of a composite is to combine the properties of its constituting building blocks in order to obtain a material with enhanced mechanical properties. Fibre-reinforced polymer-matrix composites have higher specific stiffness and strength compared to metals, as well as better resistance against corrosion and fatigue. Therefore, these materials are very attractive for lightweight applications such as aeronautics, space applications, transport, automotive sector, sports and recreation. High-quality composite components are often produced by autoclave-assisted curing. The quality of the final composite component is strongly influenced by the conditions of the autoclave cycle, i.e. cure time, pressure and temperature. To assure optimal quality of the composite part, there is a growing demand for sensors that are capable of in-situ monitoring of the curing process during the autoclave cycle. Thin-film thermocouples (TFTCs) are promising candidates to fulfill in-situ temperature sensing. Unlike more conventional fibre-, foil- or micro-sensors causing material and geometrical discontinuities when embedded in the composite material, TFTCs can be embedded without major impact on the composite?s structural life, integrity and mechanical properties. Furthermore TFTCs have negligible mass, a high degree of geometrical freedom and minimal gas flow disturbance when applied on a surface. In this work, the influence of the deposition parameters during magnetron sputtering of the TFTC on its performance (Seebeck coefficient) is presented together with a fundamental understanding of the performance of the TFTC in relation to thin film microstructure and properties.

Resume : The multiferroic bismuth ferrite (BFO) has attracted enormous attention since it shows ferroelectric/piezoelectric behavior, magnetic transition temperature well above room temperature and a rather low direct band gap (about 3 eV) which make this material suited for a wide range of potential applications such as advanced data storage devices, spintronics, sensors and energy harvesting. MOCVD grown ferroelectric BFO films have been covalently functionalized with optically active molecular monolayers based on either Eu(beta-diketonates) complexes or systems with delocalized pi-greek electrons (namely free and metaled tetra-carboxyphenyl porphyrins ) adopting a highly versatile multi-step approach. BFO films were deposited by MOCVD using a multi-metal source, consisting of the Bi(phenyl)3, and Fe(tmhd)3 (phenyl = –C6H5, H-tmhd = 2,2,6,6-tetramethyl-3,5-heptandione) precursor mixture and were characterized using X-Ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-Ray microanalysis, while the piezoelectric response of deposited films has been investigated at the nanoscale by Piezoelectric Force Microscopy. BFO surface functionalization route consists of a prefunctionalization step with bi-functional phosphonic linkers (phosphonoproprionic and aminopropylphosphonic acids), having terminal carboxylic and amino groups able to bind the molecular layers. Molecular modified surfaces were studied by X-Ray Photoelectron and fluorescence spectroscopies.

Resume : Interest in Layer-by-Layer (LbL) self-assembly thin films has been growing for the past decade. This coating technique consists in the alternating deposition of oppositely charged species on charged surface, providing new or complementary properties to a material. Due to the easy processing of this construction, the LbL coating technique can be transferred on different types and more complex surfaces whilst preserving the properties of the films. Here, we report on the construction of photocatalytic nanoscale films containing positively charges titanium dioxide (TiO2) nanoparticles and polystyrene sulfonate polyanion on model surfaces (Si wafer, quartz slides), as well as on polyester textiles, using both dipping and spraying methods. Both dipped/sprayed films exhibit a linear growth according to the number of pair of layer built on model surfaces, with a film growth monitored by ellipsometry, Quartz Crystal Microbalance, UV-Vis Diffuse Reflectance spectroscopy and microscopy. SEM analysis showed a homogeneous and porous coating of TiO2 nanoparticles, already for one single layer pair. The LbL construction was further transferred to textiles for self-decontaminating photocatalytic applications. The influence of thin film properties on their photocatalytic activity was studied taking the formic acid oxidation under UV-A light as model test reaction for indoor air remediation. Catalyst–saving nanoscale thin films with a single layer pair showed very high photocatalytic activity.

Resume : The integration of Plasmonic (metal) Nanoparticles (P-NPs) within wide band gap semiconductors is object of investigations for the possibility to enhance the performance of photovoltaic or photocatalytic thin film devices. Nevertheless, the mechanisms of coupling between plasmons and light within such nanostructures is not fully understood and key questions involving the effect of P-NPs size and dispersion still require in-depth studies. Moreover, P-NPs are often produced by liquid phase techniques and then embedded within the semiconductor film, limiting the control of the obtained structures. Here, we use vapor phase Pulsed Laser Deposition (PLD) to produce Au P-NPs and nanostructured TiO2 photoanode films. By varying the process parameters and exploiting annealing treatments, we tune Au P-NPs size distribution and the hierarchical TiO2 nanoscale morphology. Optimized Au P-NPs are coupled with TiO2, involving deposition of P-NPs at the bottom or at the top of the TiO2 as well as co-deposition of integrated TiO2/Au-NPs assemblies or multilayers. For the different architectures, we show that the plasmonic peak of Au NPs affects the optical behavior of TiO2, improving light absorption by promoting multiple-reflections and scattering. In the case of co-deposition, we show that the TiO2 growth, morphology and optical properties are affected by the Au NPs. For the best optimized systems, we discuss the results of the photocatalytic performance under solar simulator illumination.