Carbon- and/or nitrogen-containing thin films and nanomaterials

Resume : Peculiar properties of organic thin free-standing films make them potentially useful for several applications in wound healing, arterial repairs, and manufacturing of dermal substitutes. Plasma deposited thin films, since long time, have attracted the interest of researchers due to their irregular structure, high level of crosslinking and heterogeneity that can be varied by properly tuning the different plasma deposition external parameters. Oxygen containing functional groups can confer hydrophilic character to a coating and they can also be used as “anchor” groups for covalent immobilization of molecules and to elicit bio-specific interfacial responses with biological entities. In this work, thin free-standing C:H:O films containing active COOH groups, were deposited by a double step plasma approach based on CO2/C2H4 and CO2/H2 mixtures used as precursors. Plasma depositions were performed on silicon shards previously coated with polyvinyl alcohol (PVA) or a double layer of PVA and polylactic acid (PLA) in order to obtain free standing coatings floating on water potentially useful as dermal substitutes. Plasma processes developed in this research provide a simple, versatile and robust tool to synthesize ultrathin chemically asymmetric multifunctional free-standing stable (1month air storage) films rich of COOH groups. Acknowledgements: V. Mattoli, D. Pignatelli, S. Cosmai, D. Benedetti are gratefully acknowledged for scientific and lab. support.

Resume : Antibacterial thin films are intensively studied, because they represent valuable alternative approach to systemic usage of antibiotics after implant surgery. Antibacterial thin films are able to act locally, which limits the amount of antibacterial agents needed and thus dramatically reduces possible undesirable side effects. In addition, they can be synergistically used with systemic usage of antibiotics lowering thus the possibility of onset of infections. In this contribution, we will discuss two types of thin films with tailor-made antibacterial efficiency that are based on plasma polymers, concretely a) plasma polymer coatings with immobilized antibiotics and b) metal/plasma polymer nanocomposites. It is shown that in the first case the amount of released antibiotics may be tuned either by chemical composition of plasma polymer reservoir or by changing its thickness. It is also possible to alter the release kinetics by deposition of additional diffusion barriers. In the case of metal-based nanocomposites the amount of released metal ions may be varied by changing the amount of metal nanoparticles or by changing the matrix thickness. The possibility to merge both antibacterial agents into one thin film will be also presented. Acknowledgements This work was supported by grant GACR 16-14024S from the Grant Agency of the Czech Republic. J. Kratochvíl also acknowledges support from the Grant Agency of Charles University in the frame of student project GAUK 1394217.

Resume : Recently, we directly fabricated the graphene-based composite from graphite in the presence of chlorin e6 (Ce6) by sonication in aqueous phase [1]. The composite (G/Ce6) was found to deliver the Ce6 into cancer cells and work as a photosensitizer for cancer photodynamic therapy (PDT). In this paper, we used h-BN in place of graphite and realized much higher Ce6 concentration in the composite of h-BN/Ce6 than that of G/Ce6. 　Aqueous dispersion of h-BN/Ce6 was prepared by use of commercially available h-BN and Ce6 under the same conditions as those in the preparation of G/Ce6. The formation of h-BN/Ce6 was confirmed by the red shift of Q band in the absorption spectra and quenching of the fluorescence. In comparison of these dispersions, the contents of Ce6 and the carrier were 10 and 20 times larger in h-BN/Ce6 than G/Ce6, respectively. Since the size of h-BN is much smaller than that of graphite, it is concluded that h-BN was exfoliated much more easily than graphite in the presence of Ce6 in water. This is supported by the phenomenon that the loading capacity of Ce6 on h-BN is half of that on graphene. 　The cytotoxicity of h-BN/Ce6 to HeLa cells was confirmed under irradiation of 660 nm LED light. While Ce6 without carrier exhibited no cytotoxicity, viability of the cells significantly decreased to less than 20% at the Ce6 concentration of 0.2 µg/mL. This PDT effect by use of h-BN/Ce6 is quite similar to that of G/Ce6, indicating no difference between h-BN and graph ene as a drug carrier. [1] G. Liu, H. Qin, T. Amano, T. Murakami, N. Komatsu, ACS Appl. Mater. Interfaces. 7, 23402 (2015)

Resume : In this study, graphene nanoplatelets (GNP), sericin (SS) and graphene nanoplatelets/sericine (GNP–SS) composite films obtained via Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique were used as biointerfaces for pre-osteoblast cells studies. The characterization of each specimen was monitored by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurements, and Fourier Transform Infrared Spectroscopy (FTIR). The materials' surface analyses suggested the successful coating of GNP, SS and GNP–SS onto the alloy surface. Additionally, the activities of pre-osteoblasts such as cell adhesion, cytoskeleton organization, cell proliferation and differentiation potentials exhibited on these substrates were investigated. Results showed that the GNP–SS-coated substrate significantly enhanced the growth and osteogenic differentiation of MC3T3-E1 cells when compared to bare and GNP-coated alloy. Collectively, the results show that GNP–SS surface-modified Gum alloy can modulate the bioactivity of the pre-osteoblasts holding promise for improved biological response in vivo.

Resume : The multifunctional SiCN:H films have great potential for photovoltaic, optoelectronic and tribological applications. The required physical properties of these films for such applications strongly depend on their chemical composition and microstructure. This work aims at tuning the optical, chemical, microstructural, and mechanical properties of SiCN:H films by varying their Si content. These films were deposited here on Si substrates under a hybrid-plasma containing ionized tetramethylsilane, nitrogen and argon gases. This plasma was generated by combining 2.45-GHz electron cyclotron resonance (ECR) with 13.56-MHz reactive magnetron sputtering of a Si target. The rf-magnetron power was varied from 0 to 200 W so as to alter the Si content in these films. The films were characterized using SEM, FTIR, XPS, spectroscopic ellipsometry, and nano-indentation. The film growth rate increases with the rf-magnetron power and it reaches 325 nm/h under the rf power of 200 W. This rate is around 1.5 times higher than that obtained using only ECR plasma with no magnetron power. The film hardness and Young modulus rise swiftly to 10 GPa and 115 GPa respectively with the rf power up to 50 W before getting nearly stabilized with further raise in the rf power. The film refractive index at 2 eV also increases from 1.75 to 1.9 in this power range suggesting that the films become denser with the rf power. The films may be considered transparent with their small light absorption in the visible spectrum. Thus they show useful for photovoltaic cells and antireflective coatings. The above increases correlate with the augmented Si-C bonds with the rf power as deduced from XPS and FTIR spectra. The physical parameters of the SiCN:H films prepared using the hybrid plasma herein thus appear tunable by varying the film Si content. Acknowledgements : This work was supported by the French National Research Agency (HD-Plasm-A-SiNOC:H project : laboratoire PROcédés, Matériaux et Energie Solaire – Perpignan / Institut des Matériaux de Nantes / Institut de Chimie de Clermont-Ferrand / Institut Jean Lamour - Nancy –France).

Resume : The plasmonic applications require search for novel materials with metal-like optical properties and low optical losses. Transition metal nitrides exhibit metallic properties depending on a concentration of free-carrier of charge. Their plasmonic properties can be controlled by the film structure and the stoichiometry. In this work, we deal with the study of the growth process of TiN films. The films are grown by RF magnetron sputtering on fused silica, silicon and MgO substrates at a substrate temperature ranging from 20°C to 500°C. The growth process is monitored using in-situ spectral ellipsometer in the spectral range from 245 to 1690 nm. The ellipsometric data are analysed using mathematical models based on Drude-Lorentz oscillators describing the interband transitions and free-electron behaviour. The number of physical parameters such as free-electron concentration, Drude relaxation time and electrical conductivity is estimated at each stage of the deposition process by analysis of dielectric functions. Special attention is devoted to the initial nucleation stage when the free-electron behaviour is significantly influenced by the interface between the substrate and the TiN film. The prepared TiN coatings are analyzed using infrared ellipsometer operating in the spectral range from 1.7μm to 30μm where the optical functions are the most significantly influenced by free-electron behaviour. The obtained results are compared with those obtained by Van der Pauw and Hall effect measurement. The TiN film structure, chemical bonding and composition are analysed by X-ray Diffractometry, X-ray Photoemission Spectroscopy and Energy Dispersive Spectroscopy, respectively. The surface morphology is studied using Atomic Force Microscopy and Scanning Electron Microscopy.

Resume : Graphitic carbon nitrides (GCNs) represent a family of 2D materials composed of carbon and nitrogen with variable amounts of hydrogen, used in a wide variety of applications. We report a method of room temperature thin film deposition which allows ordered GCN layers to be deposited on a very wide variety of substrates, including conductive glass, flexible plastics, nanoparticles and nano-structured surfaces, where they form a highly conformal coating on the nanoscale¹. Film thicknesses of below 20 nm as well as above 300nm are achievable very controllably. In this way we construct functional nanoscale heterojunctions between TiO2 nanoparticles and GCN, capable of producing H2 photocatalytically under visible light irradiation thereby making it a good alternative to existing devices². The films are hydrogen rich, have a band gap of approximately 1.7eV, display transmission electron microscopy lattice fringes as well as X-ray diffraction peaks despite being deposited at room temperature, and show characteristic Raman and IR bands. We use cluster etching to reveal the chemical environments of C and N in GCN using X-ray photoelectron spectroscopy. We elucidate the mechanism of this deposition, which operates via sequential surface adsorption and reaction analogous to atomic layer deposition with the starting reagents derived from an Ionothermal approach to synthesise GCN flakes3. The mechanism may have implications for current models of carbon nitride formation as well as allow for controllable carbon nitride film growth, for potential thin film applications.

Resume : Transition metal carbonitride coatings have attracted great interest in various applications due to their superior characteristics such as chemical inertness, high hardness, superior lubricating properties and high wear resistance, providing extended life service of the coated parts and components TiCN coatings have poor tribological performance under dry testing conditions at high temperature, while it proved to have high tribocorrosion performance in saline solution. In this work we study the influence of Nb, Zr, Si, NbZr and ZrSi addition to TiCN coating, aiming for their use as protective layers for parts subjected to sever corrosion and wear. The coatings with C/N ratios ranged from 0.5 to 2 were deposited using the cathodic arc technique in a mixture of N2 and CH4 gases. The coatings were comparatively analyzed for elemental and phase composition, adhesion, hardness, intrinsic stress, morphology and anticorrosive properties. The tribological tests were performed at ambient and 250°C. Abrasive and oxidative wear was found to be the main wear mechanism for all of the coatings. The coatings with C/N of about 0.5 proved to be the most suitable candidates to be used in severe service conditions. We acknowledge the support of the Romanian project PN-III-P1-1.2-PCCDI2017-0239 and the Core Program-2018.

Resume : High-entropy alloys (HEAs) and high-entropy ceramics (HECs) have recently gained particular attraction in the field of materials research due to their promising properties, such as high hardness, high strength, and thermal stability. In the present work, we report on the thermal stability of high entropy nitrides to provide a deeper insight and better understanding of the high-entropy effect, according to which such materials should be stabilised in the high-temperature regime. Therefore, (HfTaTiVZr)N coatings were reactively sputtered from a single powder-metallurgically produced composite target and vacuum annealed between 1100 and 1500 °C. The structure and morphology, the chemical composition, and the thermal stability of the coatings were investigated by scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. We observe a promising thermal stability of the single-phased face-centred cubic (fcc) coatings up to 1400 °C, whereas coatings annealed at 1500 °C indicate a slight decomposition into a hexagonal phase next to the fcc matrix. As the XRD peak width remains relatively constant, we assume that the expected thermally-induced grain growth and/or decomposition takes place at significantly higher temperatures than compared to coatings like TiN and TiAlN. Our here presented results represent a promising basis for a further improvement in order to establish (HfTaTiVZr)N coatings as a candidate for (novel) high temperature applications.

Resume : Chromium or titanium nitride coatings obtained by PVD methods are widely used as hard and wear-resistant materials for many different applications, such as cutting tools, machine parts or as decorative coatings. Various interlayers, such as e.g. thin chromium coating, are used to reduce interfacial mechanical stresses and improve the coating adhesion to the substrate. In this work coatings made of S-phase (nitrogen stabilised stainless steel) were proposed as the interlayer. Composite coatings were deposited by reactive magnetron sputtering process in two steps. The deposition of the CrN coating followed the deposition of S-phase interlayer carried out in the atmospheres with varied nitrogen content, which influenced the lattice parameter of S-phase. X-ray diffraction was used to examine the phase composition and texture of the coatings, while the morphology of the composite was investigated by scanning electron microscopy. Energy and wavelength dispersive spectroscopy were used to evaluate the chemical composition of coatings. The hardness was measured by nanoindentation using the Berkovich tip and the adhesion was assessed by means of scratch test method with progressive load.

Resume : Very thin graphitic films (VTGF) (1-3 nm) are obtained from Diamond-like carbon (DLC of t-aC type) by thermal annealing performed in Ultra High Vacuum conditions in the range 973-1373 K. DLC are previously grown on transparent quartz by pulse laser deposition (PLD) of carbon at ambient temperature. The surface formation of VTGF on top of the DLC has been systematically investigated as a function of many parameters: the PLD carbon fluence (1-10 J/cm2), the DLC film thickness (1-20 nm) and the annealing temperature (973-1373K). The roughness of the films was at the atomic-scale level (< 1nm) with a high uniformity over a 10*10 mm2 area, as seen by AFM. The nature of the DLC as well as the formation of graphene films on top of DLC have been investigated by angular X-ray photoemission, Raman scattering spectroscopies Nuclear Reaction Analyses (NRA) and UV-visible optical transmission. We can thus determine the carbon sp2-sp3 content, the carbon density, the band gap which exhibit a maximum at moderate PLD fluence (5-6 J/cm2) and the atomic carbon deposition rate. Moreover, the surface conductivity exhibit a progressive increase with thermal treatment with a saturation above1173K and medium fluence (5-7 J/cm2) due to the surface transformation of DLC into graphitic films up to a complete transformation of the film. The combined high transmittance due to the very thin graphitic layers and the surface electrical transport properties might be suitable for application as transparent conductors, as deduced from the figures of merit like conductivity of transparency compared to classical ITO layers.

Resume : DLC coatings are of great interest in many industrial applications. One of the challenges is to achieve the desired functional properties of the thick coatings, such as high hardness or low friction coefficient, while ensuring structural integrity of the whole coating system, because hard DLC often suffer from poor adhesion. In this contribution we report on synthesis of micrometer thick DLC coatings on Si and metal substrates using reactive and nonreactive high power impulse magnetron sputtering (HiPIMS). The main process control parameters are the HiPIMS pulse characteristics (peak voltage, current and pulse duration), the gas pressure and gas composition (comprising of mixtures of Ar, Ne, CH4, C2H2). In order to establish a link between plasma conditions and film properties, process optimization was carried out. Both hydrogenated and hydrogen-free DLC coatings were deposited and characterized. It was found that an addition of a small fraction (only a few percent) of hydrocarbon gas leads to a substantial increase in the deposition rate without deteriorating film hardness, friction coefficient and scratch resistance. Also, a substantial wear rate reduction is obtained for hydrogenated films. A comparative characterization of films prepared at laboratory scale and industrial-scale is provided and the effect of the process parameters on the film properties is discussed. This work was supported by M-ERA Net project TANDEM through the Romanian Ministry of Research and Innovation, UEFISCDI, project No 56,57/2016, and National CORE Project 2018.

Resume : Nanoparticles of the group IB metals such as Au, Ag, Cu and their nanocomposites received a significant interest due to the presence of the surface plasmon resonance effect. Recently new applications of the plasmonic nanoparticles were considered such as self saturable absorber mirrors for fiber lasers. Copper nanoparticles have some advantages over Au or Ag such as compatibility with semiconductor device technology. However, Cu oxidation problem should be solved. In this case diamond like amorphous carbon (DLC) is very good candidate as a nanocomposite matrix material. DLC films received significant attention to their high hardness, wear and corrosion resistance as well as possibility to change electrical and optical properties of these films in a wide range. In this study hydrogenated DLC films with embedded Cu nanoparticles (DLC:Cu) were deposited by reactive high power impulse magnetron sputtering (HIPIMS) ensuring high ion and neutral ratio beneficial for formation of sp3 bonded carbon phase. Chemical composition and structure of the films was varied in a broad range by changing deposition conditions such as sputtering (Ar) and reactive (C2H2) gas ratio, sputtering pulse current, HIPIMS duty cycle and pulse time. Cu atomic concentration in DLC:Cu films varied from several atomic percents up to 60 at.%. Very different sizes of the Cu nanoclusters was observed in nanocomposite films grown by using different deposition conditions. Despite that, the maximum of the surface plasmon resonance peak of the absorbance spectra was in 600-700 nm range for all DLC:Cu films. Nonlinear optical properties of the selected samples were investigated. Possibility to use DLC:Cu films as self saturable absorbers for fiber lasers was considered.

Resume : Many thermal, electrical and mechanical applications of diamond require large area thin layers deposited on various substrates at compatible surface temperature, generally far from the high range employed with conventional growth processes. Besides, nanocrystalline diamond (NCD) films possess a nanometric grain size and a surface roughness, which is convenient for the achievement of structures based on as-grown coatings. Among the few PECVD processes allowing the deposition of NCD films at low temperature, the distributed antenna array (DAA) system, composed of microwave plasma sources arranged in a 2D matrix, enables the growth of 4-inch layers at a surface temperature below 400 °C by using H2/CH4/CO2 gas chemistry at low pressure (≤ 0.55 mbar). In this paper, we investigate a DAA system through NCD film synthesis and characterization and plasma diagnostics. The effects of growth parameters such as pressure, microwave power, substrate position and substrate temperature down to 150 °C are examined on the properties of NCD layers deposited on silicon wafers and thermosensitive materials such as piezoelectric substrates (AlN, ZnO) and polymeric substrates (PTFE, Kapton). Such multilayer structures can be used for Waveguiding Layer Acoustic Wave (WLAW), biocompatible and soft electronics devices. Furthermore, the microwave discharge is investigated in growth conditions by optical emission spectroscopy, Langmuir probe and plasma modelling through a 2D self-consistent model.

Resume : Traditionally, watch manufacturers use liquid lubricants, sometimes applied to up to 100 individual lubrication points, to achieve the required low and stable friction behaviour between components and sufficient lifetime performance. Despite the careful treatment of parts and use of specific (often customized) lubricants, after a few years, the effectiveness of the lubricants degrades through evaporation, (wear) particle contamination, etc., and as a consequences watches break down or do not perform as required. In addition, some lubrication points are very difficult to access. The goal of this study was to evaluate whether, for certain watch components, solid-lubricating coatings can be used to replace liquid lubricants. Eight different types of Diamond Like Carbon (DLC) coatings and a titanium-stabilized MoS2 coating (all commercially available, different suppliers), which had been preselected from a wider range of possibilities, were evaluated in laboratory tribological tests. The tests were carried out in air under reciprocating sliding conditions using an uncoated steel ball (4.5 mm diameter) sliding on a coated steel plate at 2N load, 10 mm/s sliding speed and at two levels of humidity, 30% and 70% RH. These conditions were chosen in order to simulate the actual use conditions as closely as possible. All tests were carried out three times to gain insight into the repeatability of the results. The friction force was recorded continuously as a function of sliding distance up to 720m, corresponding to a test duration of 20 hrs. The average wear rate of the coating was determined at the end of the test, based on surface profilometry. Scanning Electron Microscopy (SEM) was used to examine the coatings and associated steel balls after testing. In order to evaluate the performance and suitability of the coatings for the application, consideration was given to the following criteria: • Low average friction coefficient after run-in. • Short running-in distance. • Constant (i.e. not erratic) friction behaviour for the duration of the test. • Low wear rate. • Little evidence of coating wear from SEM analyses. • Insensitivity of the tribological behaviour to the relative humidity of the environment. Clear differences were observed in the friction and wear behaviour of the different coatings but this did not correlate well with coating hardness. Transfer layer formation from the coating onto the steel ball was observed in all cases and it is hypothesized that the formation of this layer is related to the running-in behaviour, i.e. the sliding distance needed in order to achieve a stable friction force. The characteristic appearance of the transfer layer, as observed using SEM, varied considerably between the coatings tested. Increasing the humidity from 30% to 70% had relatively small effects on the friction and wear behaviour. Three coatings, Ti-MoS2, a-C:H and Si-doped DLC, were found to exhibit the best performance in terms of the criteria given above. These coatings were selected for further testing using actual watch components.

Resume : Amorphous hydrogenated carbon, a-C:H, is a well-known engineering material with a wide range of applications. The combination of a-C:H with embedded metal nanoparticles results to nanocomposite materials with a vast range of applications in photonics, energy harvesting and sensors among many others. In this work, the optical response of a-C:H:Me (where Me=Ag, Cu) nanocomposite thin films in the spectral range of 1.4 to 6.5 eV, is examined, through reflectance and transmittance measurements. The refractive index, optical gap and absorption coefficient are discussed in terms of their nanoscale characteristics. The nanocomposite thin films have been prepared by sequential and/or co-deposition process in a hybrid (chemical and physical) vapor deposition system. The a-C:H matrix has been directly deposited by an RF inductively coupled ion beam source via decomposition of methane gas and the metal nanoparticles (NPS) have been synthesized by a terminated gas condensation (TGC) method and deposited after size/mass inline filtering. X-ray Reflectivity (XRR) and Diffraction (XRD) have been employed to measure the density/thickness and crystalline phases, respectively. Scanning Electron (SEM) and Atomic Force Microscopy (AFM) used to investigate the surface topography of the films and a UV/Vis spectrometer has been used to measure transmittance and reflectance of the samples grown on quartz and Si substrates, respectively.

Resume : Polyetheretherketone (PEEK) is considered as a promising biomaterial for orthopedic applications. Conventional PEEK cannot satisfy high wear resistance properties together with adequate biocompatibility for use in the fabrication of an artificial joint. In order to improve cellular adhesion and thereby influence the tissue interaction as well as tribological properties, the surface energy of PEEK can be increased by plasma surface modification. Multilayer structures play an significant role in improving biotribological properties of protective coatings. The motivation of the presented work was to apply the biomimetic principle of diatom shell to coatings and their detailed microstructure characterization as well as to characterize the effect of multilayer coatings structure on biotribological properties of their surfaces. In the presented research, the nanocomposite PTFE (Polytetrafluorethylene), implanted by silica nanoparticles, in a multilayer with very thin silicone (SiO2) interlayers has been deposited. The complex biotribological characterization together with microstructure description by transmission electron microscopy indicated that the higher the amount of interlayers in the multilayer coating the more rough the coating surface was and the better the biotribological properties were found. Acknowledgment: This work was supported by the National Science Centre (Narodowe Centrum Nauki, abbr. NCN) No: 2014/15/B/ST8/00103

Resume : In this study, CNW(Carbon Nanowall) is grown on a silicon substrate by using microwave PECVD(Plasma enhanced chemical vapor deposition), and structural heat treatment of CNW using RTA(Rapid Thermal Annealing) The results of analyzing the characteristics and the electrical characteristics are shown. Using microwave PECVD, CNW was grown for 40 minutes on a silicon substrate at 1300W and 350°C. Then, the grown CNW was subjected to a heat treatment according to temperatures of 600°C, 700°C, 800°C and 900°C. using RTA. We analyzed the structural characteristics and electrical characteristics of CNW fabricated and CNW not heat treated. In order to analyze structural characteristics, we used EDS(Energy dispersive X-ray spectroscopy) and Raman spectroscopy attached to FE-SEM(Field Emission Scanning Electron Microscope), SPM(Scanning Probe Microscopy), and FE-SEM. The cross section of CNW was analyzed by cross-section FE-SEM. The surface of CNW was analyzed with SPM and surface FE-SEM. Utilizing Raman spectroscopy, after confirming the growth of CNW, the crystal of CNW was confirmed by ID/IG ratio. Using the EDS, the element weight% and atomic% of CNW were measured, respectively. A Keithley 2400 instrument was used to analyze the electrical properties. Current and voltage of CNW were measured and resistance was calculated. CNW grown on a silicon substrate was compared with the structural characteristics and electrical characteristics of the heat treated using RTA unless heat treatment was performed.

Resume : We investigate the magnetic properties of cobalt-based nanoparticles (NPs) inserted either into carbon nanotube (CNT) or into silicon nitride nanocones (SNNC) aligned arrays. Samples have been synthesized by catalytic direct current plasma discharge and hot filaments chemical vapor deposition (DC HF CCVD) that produced array of single nanostructure with one Cobalt nanoparticle (10-30 nm) on top of each nanostructure grown normal to the surface. They are characterized by XPS, Raman spectroscopy, Solid state NMR spin echo, TEM, SEM. Magnetic domains were imaged by Magnetic Force Measurement and magnetic properties were studied by SQUIDD measurements with magnetic field either oriented along or perpendicular to the CNT axes. All the micromagnetic parameters were thus determined within the random Anisotropy Model (RAM) [1]. [1] “Manifestation of the coherent magnetic anisotropy in carbon nanotubes matrix with low content of ferromagnetic nanoparticles”, Danilyuk A.L., Komissarov I.V., Labunov V.A., Prischepa S.L., Le Normand F., Derory A., Hernandez J.M. and Tejada J., New Journal of Physics, 17, (2015) 023073/1-12.

Resume : We have followed the kinetics of the transformation of Diamond-like carbon (DLC of t-aC type on quartz) into Thin Graphitic Films (TGF) (3-5 nm) by thermal annealing performed in Ultra High Vacuum at 600-900K. DLC are previously grown on transparent quartz by pulse laser deposition (PLD) of carbon at ambient temperature. The surface formation of TGF has been systematically tuned by the evolution of the surface conductivity measured by Hall effect in the Van der Paauw configuration and by depth resolved confocal Raman spectroscopy and imagery (at the interface and at the surface) and UV-visible optical transmission. Previously to the kinetics a thin submonolayer of transition metal (Ni, Co) was evaporated. They play the role of nucleation center for the nucleation of graphitic domain as low as 773K. Conductivity measurements are correlated with evolution of the band gap and carbon density. The kinetic curve displays a sigmoid behaviour that can be relied to a classical three-steps process including 1) Nucleation of thin graphitic domains around metallic nanoparticles (5-10 nm) ; 2) growth of the graphitic domains (surface and bulk) and 3) saturation through coalescence of the graphitic domains.

Resume : Among the various synthetic approaches for graphene nanosheets, chemical exfoliation and reduction of graphite can be a straightforward manner to continuous process applications, for instance, screen printing, inkjet printing, or spray methods, etc. Despite the recent progress in reduction of graphene oxide (GO) using either chemical agents or high temperature treatment, complete removal of oxygen functional groups on GO has not been possible, resulting in a highly disordered structure of reduced graphene oxide (rGO). Here, we show a simple, chemical-free method to obtain the highly crystalized rGO within a millisecond level by irradiation of the intense pulsed light. This photothermal effect is efficient to deoxygenate the GO without any damage on both basal plane and edge site. As increasing the light energy, the reduction is gradually enhanced in low energy regime, and from at 14.4 J/cm2, the relative atomic percentage of oxygen functional groups compared to that of carbon is reaching below 7 %, which is comparable to the value of pristine graphene. To verify this photothermal effect-based GO reduction, we measured the surface temperature of the sample during the intense pulsed light irradiation, and we discuss this in the presentation.

Resume : Graphene oxide (GO) is hopeful material for scalable applications of graphene because of their mass-production feature. We have reported that defects in GO formed during its synthesis can be repaired by thermal process in ethanol atmosphere at ultrahigh temperature, and structure of the multi-layer graphene obtained is not the Bernal stacking but turbostratic [1]. Turbostratic graphene should be a candidate to improve the performance of multi-layer graphene, since theoretical calculations predict its electronic structure is similar to that of the single-layer graphene. In this study, we extend our previous study to scalable synthesis of turbostratic graphene by using porous sponge-like GO as samples. Large-area single-layer GO flakes with typical size of several tens microns were synthesized by chemical exfoliation [2]. Porous cm-scale GO blocks was prepared by freeze-dry process of the GO dispersion. The GO blocks processed in ethanol at 1800 ºC exhibit much better features of D/G-bands in Raman spectra, indicating superior crystallinity comparable to CVD-grown graphene. The volume ratio of the Bernal stacking analyzed by 2D-band was ~20 %, indicating preferential formation of the turbostratic structures. The results indicate that the ultrahigh temperature process of GO films in ethanol should be promising for scalable production of turbostratic graphene including N-doping in the graphitic lattice, and its applications to quasi single-layer electronics/phononics in future.

Resume : Recently, we have demonstrated that excitation of plasmon-polaritons in a mechanically-derived graphene sheet on the top of a ZnO semiconductor considerably enhances its light emission efficiency. If this scheme is also applied to device structures, it is then expected that the energy efficiency of light-emitting diodes (LEDs) increases substantially and the commercial potential will be enormous. Here, we report that the plasmon-induced light coupling amplifies emitted light by ∼1.6 times in doped large-area chemical-vapor-deposition-grown graphene, which is useful for practical applications. This coupling behavior also appears in GaN-based LEDs. With AuCl3-doped graphene on Ga-doped ZnO films that is used as transparent conducting electrodes for the LEDs, the average electroluminescence intensity is 1.2–1.7 times enhanced depending on the injection current. The chemical doping of graphene may produce the inhomogeneity in charge densities (i.e., electron/hole puddles) or roughness, which can play a role as grating couplers, resulting in such strong plasmon-enhanced light amplification. Based on theoretical calculations, the plasmon-coupled behavior is rigorously explained and a method of controlling its resonance condition is proposed. This work was supported by a grant to the Ministry of Trade, Industry & Energy (MOTIE, Korea) under Industrial Technology Innovation Program (no.10067533), Korea Evaluation Institute of Industrial Technology, Republic of Korea.

Resume : Nowadays, various materials are being studied, for instance, diamond like carbon (DLC) which has properties such as low friction coefficient, high hardness, mechanical wear resistance, optical transparency and high electrical resistivity, these properties can be modified used other elements such as Si, N, O, etc. The DLC thin film is very useful as a protective coating on metallic pieces such as stainless steel, but there is an issue: the low adhesion of the DLC on this type of substrate, caused by its high internal stress and low thermal stability. The structural and mechanical properties of amorphous carbon-silicon thin films deposited by rf-PECVD (radio frequency plasma enhanced chemical vapor deposition) on steel surface (ISO316L) was studied in this work. The precursor employed was hexamethyldisiloxane (HMDSO) in its liquid state at room temperature and atmospheric pressure. Those films were deposited in several self-bias and two different substrate temperatures (200oC, 300oC, at room temperature there was no deposition). The deposition pressure was 2.6 Pa and they were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, glow discharge optical emission spectroscopy, Fourier transform infrared spectrometry, profilometer measurements and nanoindentation. Our results indicate that the temperature plays an important role in the adhesion of the amorphous carbon- silica thin film with the steel surface, although at temperatures lower than 150oC the adhesion is poor. The films deposited at 200oC and 300oC with different self-bias had an excellent adhesion, the spectra Raman showed that this films are amorphous and with X-ray photoelectron spectroscopy we noticed, that the percentage of Si-C and C-C binding increase as the self- bias. The hardness of these films were of the order of 20 GPa.

Resume : Fermi line in twisted bilayer graphene at zero-energy splits into two seperated points positionned along the transverse direction of the reciprocal space. Here we focus on charge transport through an intrinsic twisted bilayer graphene (TBG) sheet. We found taht the minimal conductivity and the shot noise of TBG are sensitive to the twist defect since they exhibit an anisotropic beahavior and the minimum conductivity could be suppressed for somme specific value of twist defect while the shot noise takes the unit value.

Resume : The electric conductivity and surface energy of graphene for NH3 gas sensor was investigated. The conductivity and surface energy of graphene are known to change depending on its thickness and surface defect, and it should closely relate to the Cu substrate morphology. Cu films grown by sputtering were changed its surface morphology by varying the substrate temperature and hydrogen content. Cu films of 400 ~ 500nm thickness were deposited by radio frequency (RF) magnetron sputtering on Si wafer at room temperature, 300? and 500? with varying the hydrogen content up to 10 wt%. On this Cu film, graphene was grown by the thermal chemical vapor deposition (CVD). The surface and cross sectional morphology of Cu film, thickness and surface defects in graphene were observed by the field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). The electric conductivity and surface energy of graphene were discussed in relation to the graphene thickness, state and surface defects observed by Raman spectroscopy and AFM in influence of Cu morphology. The furrows in graphene surface were decreased with narrower columnar than equi-axed Cu morphology, and the electric conductivity improved.

Resume : Recently, Graphene Quantum Dots (GQDs) have been received great attention in the field of a new class of carbon nanomaterials and optoeletronic materials in terms of their unique photo-luminescence, non-toxicity, strong chemical stability and using cheap raw materials. So many studies about synthesis of GQDs have taken place, including: hydrothermal, soft-template, hummer's method, K-intercalation. However, synthesize GQDs with crystalline structure with controlled sized is still remained unexplored. Here, we suggest a facile synthetic route for single crystalline graphene quantum dots with uniformity via catalytic reaction. and also we investigated various measurement on a series of synthesized GQDs by size. Especially, electron microscopic images show clear and sharp edge of crystalline GQDs structure and we achieved series of results from photonic analysis

Resume : Nowadays graphene emerges as a viable material for optoelectronics due to its broad optical response and tuneable properties. Synthesised in vacuum, employing high temperature (up to 1000 oC), graphene layers can be transferred on the preferable substrate (metals, polymers, etc.) and it is a key step for the applications of graphene in electronics and optoelectronics. In this research graphene layers were deposited on copper foil by advanced microwave plasma enhanced chemical vapour deposition technique which enables synthesis of large area high quality graphene. Graphene was transferred on different substrates (SiO2, PET, PET with ITO) via etching of copper foil in different etchants. Raman scattering spectroscopy and transient absorption spectroscopy (TAS) were used to study efficiency of the transfer process and analysis of optical properties of the deposited as well as transferred layers. The analysis of ultrafast excited state relaxation dynamics in graphene revealed two time intervals where the electron cooling by thermal equilibration with the lattice and lattice cooling take place. The PET covered with ITO and transferred graphene was used as one of the electrodes in electrochromic device with Prussian blue as active material. The influence of the graphene layer on the device performance as well as correlation with the ultrafast processes taking place in the layer were investigated.

Resume : In recent years researchers have devoted much attention to study of intervalley double electron-phonon processes in single- and bilayer graphenes, which determined main strips of Raman spectra. We experimentally investigated dispersion (dependence phonon energy prom quantum energies of exiting radiation) of 2D` band in micro-Raman spectra of light scattering in single- and bilayer graphenes. D` band, as a D band are defect-activated. Its frequencies depend on wavelengthes of exiting radiation. But unlike the D band, for which intervalley electron scattering mechanism is implemented, D` band associated with intravalley electron scattering on defects. The 2D` strip is it’s overtone. Established non-monotonic, but the same of both structures dispersion nature of 2D` bands, which allowed by selection rules, and defined their half-widths are equal 10 cm-1. It’s shown that “sharpness” of the intravalley double electron-phonon resonance processes in graphenes can by used to experimental determination of localization state density maxima (or phonon energy maxima) on i-LO phonon branches in single- and bilayer graphenes.

Resume : Nanostructured materials are among the most studied materials (particularly carbon nanowalls or vertical graphenes - CNW), due to their current and potential utilization in various applications, like catalysis, electrodes for batteries and fuel cells, supercapacitors, and sensors. We already developed and presented a method suitable for CNW growth, by PECVD technique [1, 2]. By attaching metal nanoparticles, one can enhance physical and chemical properties, needed for new applications. Presently, we produced the tungsten (W) particles via PVD by using the erosion of the discharge electrode of a radiofrequency (13.56 MHz) atmospheric pressure plasma jet [3]. Thus, we synthesized hybrid architectures combining CNW and W particles. The hybrid architectures were investigated by Scanning Electron Microscopy, and Raman Spectroscopy. From the top-view SEM images we could observe that we managed to obtain CNW with W particles on their top, with different particle concentrations, depending on the growth conditions. Also, we could observe that the W particles deposited prevalently on the edges of the CNW. [1] S. Vizireanu, L. Nistor, M. Haupt, V. Katzenmaier, C. Oehr, G. Dinescu, Plasma Process. Polym., 5, 3 (2008) 263; [2] S. Vizireanu, S.D. Stoica, C. Luculescu, L.C. Nistor, B. Mitu, G. Dinescu, Plasma Sources Sci T 19 (2010) 034016; [3] A. Lazea Stoyanova, A. Vlad, A.M. Vlaicu, V.S. Teodorescu, G. Dinescu, Plasma Process. Polym., 12 (2015) 705-709

Resume : Printed electronics are of increasing interest. The substrates used have primarily been plastics although the interest for cellulose-based substrates is increasing due to the environmental aspect as well as cost. The requirements of substrates for electronically active inks differs from graphical inks and therefore we have investigated a custom-made pigment based coated paper and compared it to commercial photo-papers and a coated PE film. Our goal with the study of different substrates was to select the most suitable substrate to print water based 2D materials inkjet inks for flexible electronics. The discovery of graphene, a layered material achieved from the exfoliation of graphite, has resulted in the study of other materials with similar properties to cover areas where graphene could not be used due to the absence of a bandgap in the material. For example in thin film transistors (TFT) a semiconductor layer is essential to enable turn on and off the device. This semiconductor layer can be achieved using various materials but particular interest have been dedicated to abundant and cheap 2D materials such as the transition metal dichalcogenide (TMD) molybdenum disulfide (MoS2). To date, most of the dispersions based on TMDs use organic solvents or water solutions of surfactants. Previously we focus on the study of environmental friendly inks produced by liquid phase exfoliation (LPE) of MoS2 in water using cellulose stabilizers such as ethyl cellulose (EC), cellulose nanofibrils (CNF) and nanofibrilcellulose (NFC). We have study various aspects of the ink fabrication including pH range, the source of MoS2, nanosheets thickness, particle size distribution, ink stabilizers, ink concentration, viscosity and surface tension. These inks have very low concentration requiring a number of printing passes to cover the substrate. Therefore the substrate selection is crucial as a large amount of solvent is to be absorb by the substrate. Our goal was to use such an ink to print electrodes of MoS2 into a paper substrate after substrate selection. Commercial photo papers, a commercial coated PE film and a tailor made multilayer pigment coated paper substrate were used for the substrate selection analysis. We print the substrates using a DIMATIX inkjet printer with a 10 pL printing head using the distillated water waveform supplied by the printer manufacturer. The voltage used was 23V and 4 nozzles were used for the print outs. The inkjet ink used was the organic PEDOT:PSS. We printed lines ranging from 1 pixel to 20 pixels with 1, 2 and 3 printing passes. The printing quality was evaluated through measurements of the waviness of the printed lines measured after imaging the printed samples with a SEM microscope. The line width measurement was done using the software from the SEM. We also evaluated the structure of the coatings using SEM and topography measurements. The ink penetration through the substrates was evaluated using Raman Spectroscopy. For the pigmented coated sample we measured 4% of ink penetration through the substrate for the 1pxl printed line printed once onto the paper. Cross-section SEM images of the printed lines were made to visualize the ink penetration into the substrate. Regarding the electrical conductivity of the printed samples, the differences in resistivity varying the width of the printed lines and the number of printed passes were evaluated. The resistivity of the printed electrodes was evaluated using the 2-points probe method. Before the resistivity measurements, the printed substrates were heated at 50°C and 100°C for 30 minutes in an oven. We choose the PEDOT:PSS ink because it is a low price ink compared to metal nanoparticles inks for printed electronics. The print outs had low resistivity at a few printing passes with no need for sintering at high temperatures. The MoS2 ink has a very high resistance at a few printing passes due to lower coverage of the substrate therefore for this ink these measurements were not possible to be made. The main pigment composition of the paper coatings of the substrates was evaluated using FT-IR and EDX, these data plus the coating structure evaluated by SEM was related to the print quality. The best in test papers were used to print MoS2 electrodes. After the printing tests, another step for the optimization of the MoS2 ink properties shall be carried out in future studies for better print quality. We also evaluated the surface energy of the substrates through contact angle measurements to match the surface tension of the PEDOT:PSS ink and later the MoS2 ink. Although the pigmented coated printing substrate did not show better results than the commercial photo papers and PE foil in terms of line quality, it shows the lowest resistivity and sufficient results for low cost recyclable electronics, which do not require high conductivity. Nevertheless, the substrate was very thin and it could even be used in magazines as traditional lightweight coated papers (LWC) are used but with the additional of a printed electronic feature.

Resume : A promising way to tailor the chemical and electronic properties of graphene layers is the doping of the carbon honeycomb using heteroatoms such as nitrogen or boron. In the domain of electrochemical sensor, this may allow to control both conductivity and chemical activity. Nitrogen doped graphene was produced by the thermal annealing of nitrogen doped amorphous carbon (a-C:N) deposited either on a nickel thin film on a silicon substrate or between the silicon substrate and the nickel catalyst layer. The a-C:N thin films were produced by femtosecond pulsed laser ablation of graphite in nitrogen, while the nickel thin film was thermally evaporated. The nitrogen content and bonding configuration in the produced films were evaluated by XPS spectroscopy, with a particular attention to the ratio of pyridinic and pyrrolic bondings, the former being more interesting to control the conductivity and chemical activity of the film. The structure of the graphene was studied through microRaman spectroscopy using Raman mapping. Those results were compared to the electrochemical properties of the produced N-doped graphene films, studied through cyclic voltammetry using ferrocene as a redox probe. Electron transfer properties are compared to non-doped graphene films, which have already shown promising electrografting perspectives for advanced compound detection (1). (1) P. Fortgang et al., ACS Applied Materials and Interfaces 8 (2016) 1424-1433

Resume : Non-thermal atmospheric pressure plasma jets represent a simple technology for the modification of material nanostructure and surface chemistry. They can be applied to polymers aiming at improved adhesion of further coatings or adhesives or synthetic textiles to improved wettability and biocompatibility. We have investigated an industrial device based on gliding arc discharge working in dry air at 50 Hz. The surface modification was enhanced by an addition of gaseous additives like oxygen, water vapors or volatile organic compounds that could produce longer-lasting surface modifications. We implement a gas dynamic model of the industrial device with an extra gas flow of additives and tested “in silico” possible arrangements. The gas-phase chemistry was studied by optical emission spectroscopy. The plasma dynamics was observed with fast camera imaging. The results of plasma-surface interaction were assessed by the surface analysis of modified polypropylene.

Resume : Wetting properties of carbon nanowall (CNW) layers deposited by a plasma technique were investigated at sub-micrometer scale by Scanning Polarization Force Microscopy (SPFM). Micrometer and sub-micrometer size glycerol droplets were created on the surface of the CNW layers by an evaporation and condensation technique. Contact angle values were measured from SPFM topography images of the deposited liquid droplets. It was found that the local wettability is influenced by the local surface charging of the CNW layers which, in turn, can be controlled by applying a local bias with the conductive SPFM probe.

Resume : Graphitic carbon nitride (g-C3N4), which is an organic and graphite analogue, has attracted much attention since it has been discovered. Many researchers have focused on g-C3N4 in the field of photocatalysis and electrocatalysis. It is also an effective, stable and promising electrochemiluminescent (ECL) luminophore because of its high electron conductivity and excellent electrochemical-driven luminescent activity comparing with other ECL luminophores. In this work, an electrochemiluminescent aptasensor based on β-cyclodextrin/graphitic carbon nitride (β-CD/g-C3N4) composite for selective and highly ultrasensitive assay of platelet derived growth factor BB (PDGF-BB) is fabricated. To achieve the sensitive and specific detection of PDGF-BB, it is an available strategy to explore excellent electrochemiluminescent (ECL) luminophores with the advantages of high electrochemical-driven luminescent activity and a specific recognition function. The limit of detection was determined to be as low as 2.6×10−13 g/mL. It was observed that β-CD was playing a key role in improving the adamantane-labeled DNA amount modified on the electrode surface. It can further help to amplify the ECL quenching effect by both energy transfer and photo-excited electron transfer processes between g-C3N4 emitter and ferrocene quencher.

Resume : In this work, a very simple electrochemical sensor was proposed for brucine determination via electropolymerizing brucine imprinted poly-o-phenylenediamine (PoPD) at a single-wall carbon nanotubes (SWNTs) modified glassy carbon electrode. o-Phenylenediamine was chosen as monomer of electropolymerization, because it was proved to be easily electropolymerized on various substrate materials and form films with good chemical and mechanical stability. SWNTs were employed to enhance the electrochemical response. The obtained MIP sensor demonstrated high binding capacity, good selectivity, broad linearity and excellent reproducibility for the detection of brucine. Under the optimal experimental conditions, the current response of the imprinted sensor was linear to the concentration of brucine in the range of 6.2 ×10−7–1.2×10−5 M, and a detection limit of 2.1×10−7 M was obtained. The imprinted sensor showed high recognition ability and affinity for brucine in comparison with non-imprinted polymer (NIP), and it was successfully applied to the determination of brucine in human serum samples with recoveries of 99.5–103.2%. This sensor provides an efficient method for eliminating interferences from compounds with similar structures to that of brucine.

Resume : Thin dielectric films were deposited by matrix assisted pulsed laser evaporation (MAPLE) starting from shellac or adenine dissolved and frozen in 1 wt% in methanol. Upon the solid target irradiation with a focused laser beam emitting at 266 nm, the matrix was evaporated and shellac/ adenine active material was collected onto silicon, Au coated silicon or quartz substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques were used to investigate the morphological properties of the films. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the materials quality upon the laser transfer. Spectroscopic ellipsometry (SE), UV-VIS transmission and electrical measurements were employed to assess the suitability for utilization of the obtained organic thin films in microelectronics. Both investigated materials showed great potential in being used as dielectric layer for further integration in an OFET design, showing low dielectric losses and leakage currents.

Resume : As a flexible and transparent electrode, graphene is promising materials due to its high flexibility, transparency and electrical conductivity. For manufacturing of graphene transparent electrodes, a large area graphene sheet is synthesized on copper foil by chemical vapor deposition (CVD) [1]. After etching of the copper, the graphene sheet is transferred on a transparent and flexible polymer substrate using carrier film [1-3]. Since the graphene sheet and the substrate are laminated together, this transfer process causes mechanical damages to transferred graphene, which result in the degradation of electrical properties of the graphene electrode [4]. In this study, we identified the key failure mechanisms of transferred graphene induced by deformation of contact interface, based on the observations of mechanical damages using scanning electron microscope. To manifest these mechanisms, numerical simulations are performed using finite element models expressing mechanical deformation during the transfer process. A highly deformed region of transferred graphene in the simulation is correlated with the observed region showing mechanical damages of graphene. From the observation and the numerical calculation, we found that the high contact pressure generates large deformation and mechanical damages in transferred graphene. These results contribute to developing the manufacturing process of CVD graphene electrode. [1] J. Ryu, et al., ACS Nano 8(1), p.950-056 (2014). [2] K. S. Kim, et al., Nature 457, p.706-710 (2009). [3] S. Bae, et al., Nature Nanotech. 5, p.574-578 (2010). [4] J. Kang, et al., ACS Nano 6, p.5360-5365 (2012)

Resume : This work presents the preparation of mesoporous carbon thin films by a novel Matrix-Assisted Pulsed Laser Evaporation technique [1]. This relies on pulsed laser irradiation of a cryogenic target made of organic precursors dissolved in various mixtures of solvents. An excimer KrF* pulsed laser was used inside a vacuum chamber which allows the material expulsion from the target and the immobilization on a substrate. Tuning the laser energy or the type of solvents, thin polymer films of hundreds of nanometers with various cross-linking degrees were obtained at room temperature in very short time (10 min). No drying or thermo-polymerization step is required even for high boiling point solvents. The pyrolysis of the as-obtained polymer films result in mesoporous carbon films formation exhibiting diverse nano-morphologies and specific surface areas. The involved synthesis mechanisms of phenolic resin films were investigated is detail and two competing mechanisms, e.g., target absorption of laser wavelength and subsequent molecules transfer/interactions are proposed based on several characterization techniques. [1] E. Axente, M. Sopronyi, C. Matei Ghimbeu, C. Nita, A. Airoudj, G. Schrodj and F. Sima, Carbon 122 (2017) 484-495.

Resume : Polymer-based nanocomposites have recently received considerable attention because of their unique properties and various applications in sensors, energy, biotechnology and life science. The use of cold plasmas represents one of the successful approaches in modern processing of nanocomposites materials. The present work focuses on the synthesis and characterization of polymer-based composite materials by utilizing magnetron sputtering technique either in a multiple plasma sources configuration or utilizing a multi-component target. The substrate is exposed to RF magnetron plasma using various combination of materials presenting polymeric structure and antimicrobial or antifouling properties, namely chitosan, polytetrafluorethylene (PTFE) and silver. The topographical and morphological characteristics of the polymer-based nanocomposites surface was investigated by means of Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. The chemical composition of the obtained materials was evaluated through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) investigations. The antimicrobial activity was tested by double layer and direct contact qualitative assessment, as well as by minimum inhibitory concentration. Biofilm dynamics studies were performed in order to asses the antifouling properties of the obtained composites.

Resume : Nitrogen doping of carbon nanocones (CNCs) could extend applications of this nanomaterial, such as applications in nanosensors and nanocomposites. However, research works about influences of nitrogen doping on mechanical behaviors of CNCs are rare in the available literature. This study investigated this important issue by molecular dynamics simulations. Effects of dopant (nitrogen) concentration and temperature on compressive behaviors (including the critical strain, critical load, and buckling morphology) of open-tip CNCs were discussed. To examine these effects, the compressive behaviors of nitrogen doped open-tip CNCs as well as their pristine (un-doped) counterpart are compared. It is found that the critical strain and the critical load of the CNCs decrease with the increasing dopant concentration. The temperature effect, causing reduction in the critical strain and the critical load at a higher temperature, is less evident as the dopant concentration increases. Besides, buckling morphologies of the CNCs were observed less symmetric about their cone axes when the dopant concentration increases. Results of present research might provide some information about influences of nitrogen doping on compressive behaviors of open-tip CNCs. This information is important and beneficial to practical applications of this nanomaterial.

Resume : Cu through silicon vias (TSVs) require a low resistive diffusion barrier thin film to prevent Cu diffusion and enhance the mechanical hardness for chemo-mechanical polishing. In this work, we have investigated a short pulse plasma assisted atomic layer deposited (SP-ALD) WCN thin films. For the deep TSVs, step coverage of SP-ALD-WCN is 95% and contact resistance of Cu/WCN/Si TSVs is as low as 9 Ω/contact. The Cu/WCN/Si contact structure shows excellent thermal stability even after annealing at 800˚C for 30, which are confirmed with Rutherford backscattering spectroscopy and Kelvin method of contact resistance. 90% of Cu/WCN/Si TSVs are maintained within the 10% deviation from the initial value. In contrast, Cu/TiN/Si, Cu/TaN/Si, and Cu/WN/Si TSVs show severe deviation after the same annealing conditions. Mean time to failure analysis indicates that 95~100 % of the Cu/TiN or TaN/Si interconnect lines are failed at less than 3~7 x104 s, the life time of the Cu/WCN/Si is longer than 3x106 s. Experimentally, it is found that the excellent performance of SP-ALD WCN is due to the effect of carbon in amorphous WCN at the high annealing temperature and compressive film stress.

Resume : Interstitial dissolution of large amounts of carbon or nitrogen in stainless steel leads to formation of the so-called S-phase that has high hardness and very good corrosion resistance. The S-phase is usually produced by diffusive carburisation or nitriding at temperatures below 500°C to improve the mechanical and tribological properties of austenitic stainless steel without compromising its anticorrosion properties. Carbon- or nitrogen-based S-phase coatings can also be obtained by reactive magnetron sputtering at temperatures below 400°C, which significantly reduces the risk of nitrides formation. Reactive magnetron sputtering allows a higher saturation of the austenitic structure with nitrogen or carbon than is possible with diffusion treatment, in addition, carbon and nitrogen can be dissolved together in the austenite, which is not possible in other treatments. The aim of the research is to investigate the influence of carbon dissolved in nitrogen based S-phase coatings on their structure and properties. The coatings were obtained by RMS in the atmospheres containing argon, nitrogen and varied amounts of hydrocarbon. The deposition temperature range was 200-400°C. The chemical composition of the coatings was investigated by GDOES and WDS/EDS methods and the microstructure was studied by means of SEM. The mechanical properties were evaluated by nanoindentation. AFM/MFM was used to evaluate magnetic properties of the coatings.

Resume : Functional coatings (organic, inorganic, hybrid) can nowadays be synthesized by atmospheric plasma, which opens interesting possibilities for industrial applications. Antibacterial, anticorrosion, optically active, biocompatible, self-cleaning, superhydrophilic, superhydrophobic, sticky or repellent surfaces can be obtained. However, the still mostly empirical approach used (study of the change in the coating chemistry and properties as a function of the plasma parameters) and the many references to low pressure plasma polymerization theories lead to some limitations in the development of new coatings. Another approach, based on a deeper understanding of the physics and chemistry of the plasma itself, and its consequences on the growing film will be describe. The drastic effect of the chemistry of precursors and of the choice of the plasmagen gas (argon or helium) on the chemistry and properties of the resulting coatings will be shown. Examples of fluorinated coatings, acrylates, PEG, and ion-exchange membrane films will be described. The plasma phase, or its post-discharge, is studied using atmospheric mass spectrometry (MS), optical emission spectroscopy (OES), and electrical measurements. The obtained coatings were characterized using infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), (dynamic)water contact angle (WCA), atomic force microscopy (AFM), and profilometry.

Resume : Growth of multilayered (3-10 layers) hexagonal boron nitride (h-BN) films are of great interest as a substrate for two-dimensional van der waals (vdWs) materials due to its low surface roughness in comparison to Si/SiO2 and lack of interference with the electronic properties of the overlying 2D material [1]. Single and few-layer (2-4 layers) h-BN films have been grown on polycrystalline transition metal catalytic substrates, such as Cu and Ni, using low pressure and atmospheric pressure chemical vapor deposition (APCVD). However, the growth of multilayered (>3 layers) remains a challenge as the growth on metallic substrates is surface limited. Therefore, we grow multilayered h-BN on Ni-Cu alloy substrate and controlling the h-BN film thickness by varying the alloy substrate composition. We prepare Ni-Cu alloys by electroplating Cu on to Ni followed by thermal annealing to create alloy substrates with increasing Cu concentrations (at 10 wt.% increments from 10-40 wt.% Cu in Ni). h-BN is then grown on these alloyed substrates using APCVD at 1030°C. After growth the films are characterized using grazing angle Fourier transform infrared reflection absorption spectroscopy [2]. Scanning electron microscope and xray photoelectron spectroscopy is used to probe the h-BN crystal size and stoichiometry. The electronic properties of the film are evaluated by fabricating an MIM diode. [1] Dean, Y, et. al., Nature Nano, vol. 5, no. 10, 2010. [2] B. N. Feigelson, Nanoscale 7, 3694-3702, 2015

Resume : Energy band gap plays the crucial role in solid state materials’ optical and electronic properties. Design of artificial materials with suitable band gaps is of high priority in many fields, e.g. photovoltaics, transistors, sensors, photosynthesis, photoluminescence etc. Heteroatom-doping has usually been adopted for the electronic property tuning in solid state physics. Introduction of oxygen atoms into the h-BN lattice provides a new practical route for its band gap and magnetic property engineering. Engineering of properties of hexagonal h-BN nanomaterials via oxygen doping and functionalization has extensively been studied in theory. However, it is still unclear to what extent these properties can be modulated using such methodology because of lack of significant experimental progresses and systematic theoretical investigations. Therefore, herein, we provide comprehensive theoretical pre dictions veried by solid experimental conrmations that unambiguously answer this long-standing question. We report on the strong narrowing of the optical band gap in h-BN nanosheets and appearance of paramagnetism after oxygen doping and functionalization. Our systematic theoretical studies have predicted that the electronic properties of h-BN monoatomic sheets are tunable and their band gap can be significantly narrowed through oxygen doping and/or functionalization. These findings pave the new way for h-BN nanosheet optical, electronic and magnetic property engineering, and should breed brand-new applications of layered BN materials in optical, electrical, information and energy-related elds. Results were published in Advanced Materials journal in 2017. This work was supported by the the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS»(№ К2-2017-001)

Resume : It has been reported that the deposition of epitaxial device quality GaN films requires substrate temperatures higher than 600 C and temperatures below 300C resulted in amorphous GaN films. However, some research groups managed to deposit crystalline GaN films at low temperatures as low as 200 C using plasma enhanced atomic layer deposition (PEALD). In this study, we report on the optical properties of highly oriented (002) GaN with different thicknesses, ranging from 5 nm to 100 nm deposited on Sapphire substrates. Although the compressive stress is a result of lattice mismatch between GaN films and the substrates, it has been reported that the average strain in GaN thin films strongly correlates to the film thickness and usually changes from compressive to tensile with increasing thickness. In the present research, the evolution of the average strain, phonon positions and optical band gap energy in PEALD-grown GaN films have been analyzed. The films have been characterized from the mid-infrared to the ultraviolet spectral range by using spectroscopic ellipsometry in order to obtain the critical optical parameters including optical band edge and refractive index which helped us to understand the effect of film thickness on these parameters. The measurements indicate that the increasing trend of the refractive index (n) reverses to decreasing behavior at ~60 nm. However, we have not observed a clear correlation between optical band gap and film thickness. The lowest optical band edge values obtained from ellipsometry ~3.56 eV. Phonon modes in GaN films were studied by employing both Raman and infrared spectroscopic ellipsometry. The E1(TO), E1(LO), A1(TO), A1(LO) and E2(high) phonon modes were identified for all four samples. All the phonon peaks related to GaN are considerably blue shifted with respect to their bulk values. This particular behavior is similar to the ones observed in GaN quantum dots. The E1(TO) and A1(LO) phonon modes are following comparable trend where the phonon peak positions shift towards lower wavenumbers for increasing thickness up to ~60 nm, while the phonon peak positions move towards the bulk value for 100 nm film. E2(high), E1(TO) and A1(TO) vibrational Raman peaks ranging from 500-600 cm-1 are difficult to separate but the trending Raman peaks appear to evolve very strongly with thickness which is an indication of crystalline quality. The overall results suggested that GaN films with thicknesses above 60 nm have different behavior compared to the thinner GaN films as it was shown for GaN films grown on Si(100).

Resume : Multicomponent materials, especially high entropy alloys that form solid solutions phase with simple crystal structures, have the last few years attracted an increasing research interest. Related to these alloys are their nitride and carbide counterparts, which mainly have been investigated as thin films. Generally it has been found that the metals which form binary nitrides and carbides also form multicomponent nitrides and carbides with a cubic NaCl type crystal structure (Fm-3m) and a random occupancy of the metal sub lattice. In recent studies on sputter deposited coatings in the Hf-Nb-Ti-V-Zr-N and Cr-Nb-Ta-Ti-W-C systems with varying composition we have indeed found solid solution phases with the NaCl type structure. However, for samples with high Hf (>10 at%), or Ta and W (>24 at% each) contents also a body centred tetragonal phase (I4/mmm) was found. This phase can be understood as a tetragonal distortion of the NaCl type structure. In both systems the tetragonal majority phase coexists with the cubic phase. The cause of the tetragonal distortion is unclear. The lattice distortion due to radii differences is expected to be smaller for these samples, and no compositional differences could be detected by high resolution TEM. Several may factors be relevant and will be discussed. The importance of the tetragonal distortion is also not understood, but a phase mixture with crystallographically related phases may have large importance for e.g. mechanical properties.

Resume : The presentation shows the effect of the energy Ebi delivered into the Ti(Al,V)N film by bombarding ions on its macrostress, microstructure, mechanical properties and resistance to cracking. The Ti(Al,V)N films were magnetron sputtered on Si(111) and Mo substrates in a mixture Ar and N2 gases using a pulsed dual magnetron (DM) with a closed magnetic field. Both magnetrons of DM were equipped with TiAlV (6 at.% Al, 4 at.% V) alloy targets. It is shown that (1) the compressive macrostress in sputtered films can be well controlled by the energy Ebi using (i) the pulsed bipolar substrate bias voltage Usp with alternating negative and positive pulses or (ii) the voltage overshoots generated in the pulsed bipolar DM discharge during the pulse-off time, (2) the high value of the compressive macrostress has not to be the necessary condition for the formation of films with an enhanced resistance to cracking, and (3) the Ti(Al,V)N films with high ratio H/E* ? 0.1, high elastic recovery We ? 60%, and dense, voids-free microstructure exhibit an enhanced resistance to cracking; here H is the hardness and E* is the effective Young?s modulus. The main aim of our investigation is finding that the flexible hard Ti(Al,V)N films with enhanced resistance to cracking and low macrostress can be formed.

Resume : ZrN films have important applications in advanced nuclear reactors, fusion installations or space exploration, where there are strong radiation fields. It has been recently reported that thin films, which are nanostructured, having grain sizes usually smaller than 30 nm, behaved differently under irradiation than polycrystalline or single crystal films and materials. The absence of a relatively long-distance order allows for very short diffusion paths of irradiation generated defects towards grain boundary regions that act as sinks. Therefore, the structure and properties of such thin films are less affected by exposure to radiation than large grain films. Also, dislocations could not be trapped in such small crystal grains. Therefore, the increase of mechanical hardness after irradiation caused by the generation of arrays of dislocations that become entangled and therefore immobile, was not observed in these nanostructured films. We investigated the radiation effects on properties and structure of Pulsed Laser Deposition (PLD) grown ZrN thin films. The effects of 800 keV Ar and 1.0 MeV and 1.5 MeV Au ions irradiation on the microstructure of nanocrystalline ZrN thin films were investigated using high resolution scanning and transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry, and X-ray diffraction techniques. The results confirmed that nanocrystalline films could withstand high irradiation fluences without degrading their crystalline structure or composition. XRD investigations found that there is grain growth in such films as an effect of ion irradiation. The results are compared to those reported on polycrystalline or single crystal materials.

Resume : Metallic glasses have attracted much attention during the last decades due to their interesting properties associated with their amorphous character. Among these materials, Fe based alloys offer good wear resistance, hardness higher than conventional stainless steel and good corrosion resistance when the Cr content is high enough. In this work, we study the properties of such compounds prepared as thin films by magnetron sputtering. The main experimental parameters are the applied power to each sputtering target, the working pressure and the applied bias voltage (polarisation of the substrate). In this work, FeCr, CrC and FeCrC metallic glasses were synthesized. The utilization of a combinatorial approach combined to spatially resolved structural and mechanical property measurements allowed to establish the correlation between the nano-hardness (H) and the chemistry and crystalline constitution of the films. From our data, it appears that H is largely influenced by the carbon content in the film [C], most precisely by the presence of carbide phases. More precisely, a stable value of about 6 GPa is observed for [C] < 25 at.%. For [C] ~25 at. %, H increases until ~8,25 GPa and then decreases for higher [C]. On the other hand, we also highlight the strong influence of the ion bombardment of the growing films on the mechanical properties. Specifically, for the FeCrC films, an increase of 20% of H is obtained for a bias of -100 V.

Resume : Contrary to Fe, Co or Cu nitrides, the Ni ones are scarcely studied. Thus, the binary Ni-N system is not well defined. It contains a stable hexagonal phase that exhibits a Ni3N formula. Although another nitride (Ni2N) has been also reported, the structure and the properties of this material are not clearly detailed in the literature. Nickel nitride thin films have been deposited at room temperature on glass and silicon substrates by reactive sputtering of a Ni target in various Ar-N2 atmospheres. The increase of the N2 partial pressure allows the deposition of either pure Ni3N or Ni2N films. Biphased films can be also deposited with the use of a N2 flow rate ranging between those necessary to deposit single phase. Electron probe microanalysis has been used to determine the Ni / N atomic ratio in as-deposited films. Ni2N films exhibit a preferential orientation in the [110] direction. Cumulative X-ray diffractogram obtained at various  angles has been used to show that Ni2N crystallizes with a primitive tetragonal unit cell. Full profile refinement using a Rietveld method confirmed the atomic arrangement proposed by ab initio calculation. Ni2N films have been annealed from 100 to 300 °C. XRD analyses of films annealed at 100 and 150 °C show a slight shift of the Ni2N (110) diffraction peak position due to a progressive denitridation. In addition to Ni2N, Ni3N is evidenced after annealing at 200 and 250 °C. Finally, metallic nickel is observed after annealing at 300 °C.

Resume : Increasing political and social pressure on manufactures demonstrates that producing cheap is not enough. Longer lasting as well as environmental friendly products, tools and processes are demanded. One major contributor to achieve these goals are coatings for tools and component surfaces, that are under severe stress. While conventional hard coatings are well established, a new generation of functional coatings is pushing beyond mechanical properties. Some transition metal based coatings aim to combine excellent mechanical properties with an optimization of friction and wear by interacting with lubricants to form low friction tribofilms. Molybdenum and tungsten based nitride and carbide coatings were prepared by physical vapour deposition and their mechanical, structural, and chemical properties were investigated with nanoindentation, energy dispersive x-ray spectroscopy, X-ray diffraction, and transmission electron microscopy. The most promising coatings, based on these investigations, were subjected to tribological investigations in lubricated contacts. While an in-situ generation of MoS2 and WS2 between the coatings and a sulphur agent in the oil was already discovered, this work addresses the need for a “green” alternative to conventional sulphur based oil additives. Due to the much lower sulphur contents in “green” additives, the coatings need to be tailored to these “green” additives to allow for the formation of effective lubricating tribofilms.

Resume : The BAC model coupled to k.p theory and Pikus-Bir theory was used to determine the electronic properties of GaNxAs1-x-yBiy strained highly electronegativity alloys. This investigation was performed at room temperature in terms of electronic band structure, energy levels and spin-orbit splitting energies and with a bismuth and nitrogen concentrations range varying from 0 to 12%. The incorporation of a small N or Bi content affects the strain types and induces a large variation in the properties of these semiconductors. As results, we note essentially that, for strained GaAsBi and GaAsN ternaries, a significant reduction of the bandgap energy E_g^c of about 54 meV/%Bi and 99 meV/%N were found, respectively. In addition, the spin-orbit splitting ?_(0 )^cwas increased by 39meV/%Bi for GaAsBi and decreased by 5meV/%N for GaAsN. On the other hand, for typical concentrations (x = 4% ; y = 5%) of strained GaNxAs1-x-yBiy, the energies E_g^c, ?_(so ) and the valence band splitting VBS are equal to 0.66 eV, 0.54 eV and 17 meV respectively. Finally, we applied these results in the investigation of GaAs/GaN.03As.90Bi.07/GaAs and GaAs/GaN.02As.93Bi.05/GaAs single quantum well structures under compressive stress emitting at 1.3 and 1.55 ?m./ Keywords : GaNAsBi/GaAs ; k.p theory ; BAC model; Strain structures ; 1.3 and 1.55 ?m emissions

Resume : Nitrogen (N)-containing plasma deposited organic coatings (PP) are attractive in numerous technological contexts, particularly for biomedical applications. Over the last years, our group has performed research aimed specifically at improving the performance of these films for defined applications. We have first investigated how to expand the possible available chemical compositions for N-rich films intended for contact with liquids. We performed fundamental comparative studies of plasmas and films generated from single monomers, such as allylamine, and precursor mixtures, such as ammonia and ethylene, highlighting reaction mechanisms and strengths of both approaches. The stability in water of coatings was optimised by introducing monomers favouring cross-links like 1,3-butadiene. Well-established and some lesser-known analytical techniques have been combined to provide the best possible chemical and structural characterisations of the films. The behaviour of the films in biologically relevant environments was studied. We measured the surface potential of films before investigating the effect of surface chemistry and surface charge on relevant protein adhesion and cell adhesion allowing us to derive a series of indicators for these phenomena. Other application relevant properties, such as mechanical resistance and stability to sterilization were also evaluated. N-rich films were also deposited on nanomaterials, such as multi-walled carbon nanotubes, yielding pH responsive surface and nanofluids, which can be used for transport of CO2, water or organic molecules. General guidelines for the development of N-rich plasma polymer films for applications are presented. Keywords: Plasma polymers, biomaterials, plasma polymers, carbon nanotubes

Resume : Plasma polymer fluorocarbon (PPFC) thin film is functional material with high transparency, insulation, water repellency, oil repellency and excellent surface hardness. The PPFC thin film refers to a substance formed through a glow discharge using fluorinated polymer materials such as polytetrafluoroethylene (PTFE) or a fluorinated organic gas such as CF4, C2F6. In this study, we fabricated composite targets to realize high hardness and water-repellent thin films and investigated the effect of carbon concentration and sputtering condition on PPFC thin films. Carbon nanotubes/PTFE, graphite/PTFE composite targets were prepared by press molding process. PPFC thin films were deposited by using mid-range frequency sputtering. As the sputtering power density was increased, the light transmittance and the surface water repellency of the thin film were improved, which resulted from fluorine atom concentration in thin films. The surface hardness of the PPFC film reached 4.75 GPa, which is due to the increase of the sp3 and sp2 carbon bonds. PPFC thin films ware not cracked when repeated 10,000 times bending test at radius of 10 mm.

Resume : Over 50 years, plasma polymerization has become a well-established technique for the synthesis of solid organic functionalized thin films referred as plasma polymer films (PPF). Since most of previous studies focused on the modulation of the chemical composition of PPF, the current work addresses the control of the mechanical properties of PPF by an almost unexplored approach, namely the regulation of the substrate temperature (Ts). As a case study, propanethiol was used as a precursor. By means of AFM approach-retract curves, it has been shown that the nature of the propanethiol PPF is dramatically affected by the thermal conditions of the substrate: from a high viscous liquid (? ~ 106 Pa.s.) to a visco-elastic and finally to a hard pure elastic solid (Young’s Modulus > 10 GPa) material when increasing Ts from 10 °C to 45°C. This behaviour is correlated with a pronounced increase in the cross-linking degree of PPF evaluated by ToF-SIMS measurements when increasing Ts. This evolution is ascribed by an increase with Ts in the flux of energy provided to the growing film by bombarding ions and normalized with respect to the total amount of matter deposited. Taking advantage of the knowledge gained in the first part of the work, an original method involving a high viscous PPF covered by a hard coating (i.e. Al or stiffer PPF) is established in view of the fabrication of pattern with tuneable dimensions (from the micro to the nanometer range) and shapes (e.g. wrinkle, beads).

Resume : Electrospinning is an efficient technology capable of producing polymer fibers with diameters in submicron range. It has drawn a remarkable attention during the last decade because various polymers can be electrospun at relatively low cost. The envisaged applications of electrospun fibers include protective clothing, filtration, tissue engineering scaffolds and drug delivery systems. Synthetic polymers offer easier processability for electrospinning and more controllable nanofibrous morphology than natural polymers but it is necessary to modify their functional properties. Plasma treatment is a well-established method for modification of polymer surfaces but plasma polymerization of thin films brings more versatility into final functional properties and better stability of the surface modification. Nanoscopic conformality and penetration depth of plasma polymerization is an interesting question related to the successful application of plasma technologies for modification of electrospun mats. It was found that the penetration depth can significantly differ when different processes, e.g. low pressure plasma polymerization of hexamethyldisiloxane, cyclopropylamine or atmospheric pressure polymerization of maleic anhydride and acetylene, are compared. Besides, the paper discusses the challenges encountered during the characterization of delicate polymer nanofibrous mats by electron microscopy and other techniques.

Resume : Though being more stable than wet-chemical counterparts, a drawback of functional plasma polymer films (PPFs) is still related to their limited stability in aqueous media due to swelling and degradation. In particular, amine-functional PPFs were found to be prone to oxidation and hydrolysis reactions. To improve the stability of PPFs while maintaining a suitable amount of available functional groups, vertical chemical gradients in PPFs were thus explored. Starting from the deposition of cross-linked, amine-poor films terminated by nm-thick less cross-linked layer, yet richer in amine-functional groups within a one-step NH3/C2H4 plasma process, migration and degradation processes can be effectively hindered. A comprehensive study involving plasma diagnostics (OES) and surface characterization methods (XPS, ToF-SIMS, AFM, contact angle, zeta potential) was performed to define a suitable vertical gradient nano-architecture. Finally, the stability in water was compared for two amine-containing PPFs, i.e. a monolayer (reference) PPF and a gradient-containing PPF (with 2 nm functional terminating layer). While the monolayer lost all –NH2 groups after the first day immersed in water, the well-defined vertical gradient structure preserved a constant number of –NH2 groups (~1 at%) at least up to a week stored in water. Chemical processes to support the stabilization of amine-functional surfaces are discussed. Such films are relevant to e.g. attach bio-linkers and proteins, some examples also including micr-patterning will be shown. Adjusting the thin film architecture of plasma polymer films thus provides an additional parameter to modulate surface properties of materials offering unique opportunities for biomaterials and chemical engineering.

Resume : Carbyne or sp1-carbon is the most intriguing and least studied one-dimensional allotropic form of carbon. Macroscopic carbyne crystals have not yet been synthesized due to the low stability of carbon chains. At the same time, their analog – linear-chained carbon (LCC) – can be produced in the form of a stable film hundreds of nanometers thick [1]. One of the problems that arise in the synthesis of LCC is the lack of rapid characterization technology, which confirms the structure of the new material. At the same time, the XPS and Raman scattering methods are able to detect carbon chains and reveal their structural features [2]. A possible distinguishing feature of carbyne is the presence of characteristic Raman bands near 1950 cm-1 to 2300 cm-1, that are weak and blurred in case of linear-chained carbon [2]. In this paper, Raman spectra were studied together with spatial Raman intensity maps for a sample with 200 nm LCC layer on a copper substrate in order to find new characteristic lines in low-frequency range below 700 cm-1. XPS spectra were used to confirm the chemical composition and carbon hybridization for the samples under study. Mapping results showed altered adhesion of LCC films on different faces of a polycrystalline copper substrate. 1. V. Babaev, M. Guseva, V. Khvostov, et al. in “POLYYNES - Synthesis, Properties, Applications”, edr. F. Cataldo (CRC press, USA, 2005) pp.219-252. 2. E.A. Buntov, A.F. Zatsepin, M.B. Guseva, Y.S. Ponosov. Carbon 117 (2017) 271-278.

Resume : This work describes the procedure for obtaining multi-layered structures based on amorphous hydrogenated carbon and fluorinated carbon materials and reports on the properties of such structures. The experimental set-up is based on the sequential utilization of a RF (13,56 MHz) Plasma Enhanced Chemical Vapor Deposition (PECVD) source operating in Ar/methane admixture, for the synthesis of amorphous hydrogenated layers, and RF magnetron sputtering source provided with polytetrafluorethylene target which insures the Physical Vapor Deposition process (PVD) for obtaining fluorinated carbon layers. The effect of the argon flow, RF power and deposition time associated to each sequence on the deposition rate, morphological and chemical composition of the planar structures was investigated. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques were involved to characterize the surface and cross-section features of the films and multi-layers structures. Chemical composition was revealed through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) investigations, including in-depth measurements, in order to investigate the possible diffusion of fluorine in the hydrogenated layers. Electrical properties of the structures are discussed from the prospective of their utilization in microelectronics.

Resume : Two-dimensional (2D) layered transition metal dichalcogenide (TMD) as visible light photocatalysts has attracted increasing attention due to their unique band structure and high optical stability. Here, two-dimensional MoS2 nanosheets/reduced graphene oxide (2D-MoS2/RGO) composite films were synthesized via a facile hydrothermal method using MoO3 and KSCN as source materials, in which Mo(OH)x colloid particles produced from the weak hydrolysis of MoO3 could be uniformly adsorbed onto GO mono layer and form Mo-O-C bonds by electrostatic interactions. Interestingly, after hydrothermal reaction, the uniform and monodispersed 2D-MoS2 nanosheets were founded to be vertically in-situ grown on the surface of RGO monolayer, which might be attributed to a synergistic effect between MoS2 and RGO. Prominently, the photocatalytic activities of MoS2/RGO nanocomposites for 200mg L-1 of methylene blue (MB) solution under visible light irradiation were much higher than that of pure MoS2 flower-like spheres, which suggest that the combination of MoS2 with RGO could effectively promote the separation of photogenerated electron-hole pairs and enhance the charge transfer.

Resume : The recent progress in supramolecular and dynamic chemistry triggers exciting opportunities for the tailored design of reversible ensembles for stimuli responsive functional materials. The incorporation of this stimuli-responsive fragments in the materials working as functional gates in response to temperature, pH, electric and magnetic fields, biological or redox agents offer new opportunities for the preparation of smart nanostructured material on demand. In this light, I will present our recent advances on the design and synthesis of functionalized carbon nanostructures for the construction of tailored self-assembled architectures.

Resume : Terahertz cavity-enhanced optical Hall effect (OHE) measurements are employed to study free charge carrier properties in epitaxial graphene (EG) grown on semi-insulating 4H-SiC(0001) substrates. As-grown monolayer (ML), quasi-free-standing ML and bilayer (BL) samples are investigated. An optical model based analysis of OHE data reveals a strong in-plane anisotropy of the free charge carrier mobility for the quasi-free-standing BL samples, which also have the highest mobility and mean free path parameters compared with the rest of the samples. The as-grown ML and quasi-free-standing ML samples show only weak or no anisotropy within the sensitivity of the OHE measurements. Combining the OHE results with surface morphology investigations, we were able to correlate the directions of the high and low mobility axes, with the orientation of the steps formed on the SiC substrate, where the higher mobility axis is oriented along the step edges. LEEM and micro-LEED measurements reveal a homogeneous distribution in number of EG layers at the terrace and step edge regions, and an uniform intercalation process for the quasi-free-standing BL graphene samples. We attribute the scattering of free charge carriers from step edges to variation of surface potential due to detachment of graphene from the SiC. Furthermore, we show that the higher mean free path parameters, resulting in more carriers scattered from the step edges, can affect the observed anisotropy in free charge carrier mobility.

Resume : Carbon nanomaterials reactivity towards foreign gases is very poor, limiting their potential applications in many fields, from sensing to catalysis. To meet specific requirements demanded by the applications, chemical modification of pristine carbon nanomaterials is then essential to enable an improved sensitivity to atoms and molecules adsorbed on the modified carbon surface. The activation of the surface with the creation of active sites is the essential part of a working catalyst as well as for gas or bio sensing for the interaction with foreign species. Being very sensitive to local perturbations, any modification of the lattice produces suddenly evident changes in the density of states, caused by the tuning of the charge carriers [1]. Within this context, we present the nitrogen doping of both graphene and carbon nanotubes and their characterization through synchrotron-based photoelectron spectroscopy and microscopy techniques. The nitrogen is introduced by a plasma based post-synthesis method, which allows a controlled dosing of the dopants and a tuning of the different species by changing the temperature annealing [2]. The catalytic and sensing properties of these doped nanostructures will be discussed from different points of view: UHV in situ synchrotron experiments to monitor the oxygen dissociation on graphene and the role of the different nitrogen components, as well as the study of the catalytic and sensing activity of carbon nanotubes. 1. M Scardamaglia et al., 2D Materials 3, 11001 (2016). 2. M. Scardamaglia et al., Scientific Reports 7, 7960 (2017).

Resume : Over the last 30 years, a variety of nanocarbons were discovered, e.g., fullerenes, carbon nanotubes, graphene, carbon nanohorns. They share key features such as an extended sp2 structure, and the resulting unique electronic properties, which made them popular components for advanced functional materials.1 Their composites and derivatives found diverse applications in catalysis,2 tissue engineering,3 biomaterials for medicinal use,4 to cite a few. However, they differ in morphology, and thus in physical parameters such as curvature and porosity, which affect key physico-chemical properties, including reactivity and dispersibility. Consequently, diverse is their ability to be functionalized and to interface with other components to yield functional composites, especially for use in water. The influence of nanocarbon morphology on the performance of their derivatives is often a factor difficult to anticipate. The effect of nanocarbon morphology on diverse applications has been investigated and we report on the most recent findings for uses such as, catalysis in environmentally-friendly processes,5 flexible supercapacitors,6 regenerative medicine,7 and more. In conclusion, the shapes of nanocarbons can affect dramatically their performance and the resulting properties of the final materials that contain them, and as we understand more of this process, we can advance our ability to effectively implement their use and bring innovation in everyday life uses. References: 1. Beilstein J. Nanotechnol. Thematic Issue "Advances in nanocarbon composite materials" 2017, 8. 2. M. Melchionna, et al. Catal. Today 2016, 277, 202. 3. S. Marchesan et al. Nano Today 2016, 11, 398. 4. D. Iglesias, et al. Curr. Top. Med. Chem. 2016, 16, 1976. 5. D. Iglesias et al. Chem 2018, doi: doi.org/10.1016/j.chempr.2017.10.013. 6. D. Iglesias et al. ACS Appl. Mater. Interfaces 2018, doi: 10.1021/acsami.7b15973. 7. S. Marchesan et al. Science 2017, 356, 1010.

Resume : Graphene oxide quantum dots (GOQDs) have recently been proposed as fluorescent sensors for metal ions dissolved in water. The physical origin of this fluorescence is still not completely clear, therefore further studies on GOQDs and their properties are required. A novel type of graphene-like quantum dots were prepared by oxidation and unfolding of commercial buckminsterfullerene. This process was carried out by a modified Hummer method [1]. The reaction was stopped with the addition of H2O2 and concentrated NaOH was used to acquire the solution with pH=8. After dialysis, the solution was diluted with deionized water and dried to obtain the unfolded fullerene. The metal ions were incorporated into GOQDs by adding the metal-salt water solution to the stock solution of unfolded fullerene. The properties of GOQDs before and after incorporation of metal ions (Hg2+, Cd2+, Pb2+ and Cu2+) were characterized by using AFM, FT-IR, UV-vis and fluorescent spectroscopies and XPS. In XPS, a particular attention was given to the analysis of photoemission C 1s and Auger C KVV spectra [2] in order to determine the changes in carbon electronic configuration after incorporation of metal ions into GOQDs. Depending on the preparation conditions, the quantum dots were composed of graphene oxide or graphene. [1] C.K. Chua, Z. Sofer, P. Šimek, et al., ACS Nano. 9 (2015) 2548. [2] S. Kaciulis, A. Mezzi, P. Calvani, D.M. Trucchi, Surf. Interface Anal. 46 (2014) 966.

Resume : Form-factor free and stretchable electronics, such as stretchable displays, stretchable sensor, stretchable interconnectors, and stretchable energy harvesting devices have attracted great interest for the last several decades to apply in wearable electronics. Among several key components in wearable electronics, highly stretchable interconnectors is very important because performance and reliability of wearable electronics are critically affected by electrical and mechanical properties of stretchable interconnectors. In this work, we report on the feasibility of polytetrafluoroethylene(PTFE) and Ag hybrid films prepared by co-sputtering of metal Ag target and CNT-PTFE targets as a highly stretchable interconnectors for wearable electronics. By co-sputtering Ag and PTFE on a thermoplastic polyurethane, we fabricated Ag-PTFE nanocomposite electrode with sheet resistance of 30 Ohm/square and stretchability of 30%. Compared to stretchability (~5%) of sputtered Ag film, the Ag-PTFE nanocomposite electrode showed much higher stretchability and better mechanical properties due to existence of stretchable PTFE matrix. In addition, the sputtered Ag-PTFE nanocomposite electrode showed hydrophobic surface, which is beneficial for wearable electronics. Furthermore, we demonstrated feasibility of the Ag-PTFE nanocomposite films as stretchable interconnectors and electrodes. Successful operation of LEDs connected by the stretchable Ag-PTFE interconnector indicates potential of the Ag-PTFE films as a promising stretchable interconnector materials. The hydrophobic surface of the Ag-PTFE based stretchable thin film heaters makes the surface of wearable thin film heater very clean from raindrops or sweat of human.

Resume : Graphene is a promising 2D nanomaterial for several applications in optoelectronics and light harvesting because of the combination of extraordinary properties and a peculiar low-dimensional morphology. Despite its good chemical stability, graphene features a strong sensitivity to the environment through charge-transfer processes driven by interactions with the substrate or adsorbed molecules. In this context, one of the most challenging purposes is to employ its sensitivity for the development of nano-scale devices. To this aim, here we report a study of charge-transfer processes based on the interaction between graphene and simple molecules or nanoparticles. The first process involves the adsorption of O2 molecules intercalated between graphene and SiO2 substrate by thermal treatment, and the consequent static electron-transfer from graphene to O2. By Raman Spectroscopy, we give an experimental evidence of the resulting p-type doping of graphene. The second process arises in graphene decorated with carbon nanodots (CDs). We show the photoinduced electron-transfer from the excitons within fluorescent CDs to the electronic structure of graphene, when close contact of the surface orbitals of CDs and the delocalized orbitals of graphene occurs. The interplay of graphene doping and thermal effects on surface states of CDs is deepened by thermal treatments in controlled atmosphere to evidence the tunability of the Fermi level and of the charge transfer process.

Resume : Graphene is a two-dimensional sp2-hybridized network of carbon atoms with one atom thickness, and has been recognized as an important material for electronic devices due to its unique electronic properties. Different methods can be employed to obtain single layer graphene films such as mechanical exfoliation of graphite, epitaxial growth of graphene on SiC substrate and most feasible one is chemical vapor deposition (CVD) on metal (Cu, Ni) substrate [1-3]. In electronic applications, tuning of fermi level by controlled doping because of zero band-gap is a very important factor. There are many different approaches introduced to tune the electronic properties of graphene which include electron or ion beam irradiation, deposition with metal, absorption of gas molecules, and chemical or electrochemical doping [4-7]. In this study we demonstrated the modification of electronic properties and formation of pn-junction on a single layered CVD grown graphene by deep ultraviolet light (DUV) irradiations in oxygen ambient and deposition of Al2O3 by pre H2O-treated atomic layer deposition. A selected region on the graphene is deposited with Al2O3 and the remaining uncovered region is exposed to DUV light in controlled oxygen environment. The shift in the G and 2D bands in Raman spectra suggests p and n-doping in graphene field effect transistors. The deposited Al2O3 together with pretreated-H2O and oxygen-deficient ALD environment consumes OH bonds and by surface charge transfer, shifts Dirac point to negative gate bias and introduces n-type doping. The oxygen molecules react with graphene in the presence of UV light to produce oxygen containing groups and form a stable structure on the sites of pristine graphene and induce p-type doping. The Dirac point shifts towards the positive gate voltage with increasing time DUV light exposure and it reveals the strong p-doing. Thus implying these two procedures on selected regions of a single graphene sample, we constructed pn-junction and investigated it with gate voltage dependent current–voltage characteristics. References: 1 K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, Science, 2004, 306, 666. 2 J. Hass, W. A. de Heer and E. H. Conrad, J. Phys.: Condens. Matter, 2008, 20, 323202. 3 K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim, K. S. Kim, J. H. Ahn, P. Kim, J. Y. Choi and B. H. Hong, Nature, 2009, 457, 706. 4 J. Yan, Y. B. Zhang, P. Kim and A. Pinczuk, Phys. Rev. Lett.,2007, 98, 166802. 5 M. Z. Iqbal, A. K. Singh, M. W. Iqbal, S. Seo and J. Eom, J. Appl. Phys., 2012, 111, 084307. 6 M. W. Iqbal, A. K. Singh, M. Z. Iqbal and J. Eom, J. Phys.: Condens. Matter, 2012, 24, 335301. 7 B. Wang and S. T. Pantelides, Phys. Rev. B, 2011, 83, 245403.

Resume : Carbon nanostructures have attracted increasing interest in the past two decades due to their singular properties and their potential applications in the field of nanotechnology. Unfortunately their exploitation on large scale is limited by the costs of efficient metal catalysts for synthesis via chemical vapour deposition (CVD). However, metals or metal oxides, in small or even trace amounts, can be easily found in almost all natural materials and they are in the ideal form to be used as catalysts for carbon nanomaterials synthesis via CVD route. Here we report on the synthesis of carbon nanotubes obtained via CVD route using natural mineral oxides, in particular limonite laterite, as catalyst source. The synthesized structures were carefully characterized by means of XRD, ESEM, TEM and micro-Raman spectroscopy. Furthermore, the temperature effect of reaction chamber on the catalytic activity and graphitization properties of the produced carbon nanotubes has also been studied. Our results indicate that the uses of natural mineral oxides for the synthesis of carbon nanostructure can be a suitable approach to scale up the production for specific technological applications.

Resume : Graphene and MAX phases belong to carbon based advanced functional materials. Moreover, graphene, together with MXenes recently obtained from MAX phases, are 2D materials. In the case of MAX phases, they can be also nitrogen based. CVD graphene, epitaxial graphene on SiC, solid state synthesis and sintering of MAX phases all represent forefront production technologies of these materials and high temperature is a common denominator to all these technologies. Due to high temperatures, such technologies become demanding in many ways, for instance system and materials purity, durability, costs etc. Induction heating, Laser annealing, Spark Plasma Sintering (SPS) or Field Assisted Sintering Technology (FAST) are some of the usual techniques of choice. We bring a microwave heating technique to a higher level for an ultra rapid and ultra efficient synthesis and processing of graphene and MAX phases. High-vacuum compatibility of the design is an excellent advantage. A customized multimode cavity is used. Graphene is produced by thermal decomposition of SiC surface in vacuum or by means of carbon segregation from a solid metal followed by catalyzed graphitization (graphenization). Ti3SiC2 and Nb4AlC3 MAX phases were produced from elements. Thanks to the nature of the microwave heating and system design, the heat is generated directly in the sample circumventing any need for heat transport and outstanding temperature ramp up times are achieved (single seconds for T > 1500°C).

Resume : Carbon nanotubes are promising membrane materials with their diameters in the nanometer range and atomically smooth surface.There are many efforts to prepare carbon nanotube membrane using vertically aligned or random carbon nanotubes, however, it remains a challenge to prepare carbon nanotube membrane that offers both high selectivity and high flux. Holey carbon nanotube-based membrane is developed as a new approach to make use of carbon nanotube inner diameter. The permeability of membrane depends on the carbon nanotube materials and the thickness of membranes. The resulting carbon nanotube-based membranes were used for nanofiltration of organic dye and metal nanoparticles, further examples for water treatment were demonstrated.

Resume : One of the more interesting ways to provide a material with multi-function ability is to change the surface by using a nanocomposite coating, each component giving a specific function. Such is the case of carbon and/or nitrogen-based thin films containing Ag nanoparticles. A great variety of functions are expected for both the silver (surface plasmon resonance, self-lubricating ability and antibacterial effect) and the matrix (wear resistance, low friction, high thermal stability, dielectric behaviour), which acting in sinergy can give rise to an important improvement of the final perfomance of the mechanical part. In this talk, the effects of silver nanoparticles on the functional properties of ceramic-Ag nanocomposites will be reviewed. The chemistry, structure, morphology and topography of the coatings will be analyzed as a function of the distribution, amount and sizes of the silver nanoparticles, which are dependent of the deposition strategy and process variables. The combined knowledge of the properties and Ag nanoparticles / matrix arrangements will be fundamental for the understanding of the functionalities of these materials, in particular the optical, mechanical, tribological, electrochemical and biological behaviour. Important phenomena such as the surface plasmon resonance, self-lubricating ability and antibacterial effect of silver combined with factors such as silver diffusion, segregation and ionization, will be shown to determine that functional behaviour.

Resume : This work focuses on the effect of Y, Ho, Mo, Zr and Ta addition into hard and thermally stable Hf-B-Si-C-N films in order to improve their optical transparency or electrical conductivity. The combination of the sufficiently high hardness, high thermal stability in air and optical transparency or electrical conductivity opens up a new scope of applications involving high-temperature protection of electronic and optical elements or capacitive pressure and tip clearance sensors for severe oxidation environments. Hf-B-Si-X-C-N films were deposited onto Si(100), SiC and glass substrates using pulsed magnetron co-sputtering of a single B4C-Hf Si-X target in Ar + N2 gas mixtures. A planar unbalanced magnetron was driven by a pulsed dc power supply operating at a repetition frequency of 10 kHz with a fixed voltage pulse length of 50 μs. The total pressure was 0.5 Pa and the substrate temperature was adjusted to 450°C during the deposition on the substrates at a floating potential. All Hf-B-Si-X-C-N films possessed a sufficiently high hardness (close to 20 GPa), low compressive stress, high elastic recovery and high oxidation resistance in air at elevated temperatures (above 1000°C). Addition of Y and Ho into the Hf-B-Si-C-N films prepared at the 25% N2 fraction in the gas mixture resulted in enhancement of the optical transparency. Addition of Mo and Ta into the Hf-B-Si-C-N films prepared at the 15% N2 fraction in the gas mixture led to an increase in the electrical conductivity.

Resume : Surface functionalization by advanced coatings deposition to improve the tribological and corrosion resistance properties of metallic parts is an essential requirement for surfaces such as those of medical devices like medical tools or spine implants. In the frame of the presented research, advanced Zr-Mg-Ag(Pt) nanocomposites coatings as well as Zr/ZrxN a-C:H and Ti/TixN a-C:H nanomultilayer coatings, were subjected to wear and corrosion resistant properties analysis. The main goal of the presented research was to describe mechanical and corrosion wear mechanisms of advanced nanocomposite and multilayer coatings by the application of the scanning and transmission electron microscopes. The wear mechanisms have been described ex situ and in situ by SEM and by TEM techniques. The analysis indicated that the formation of a hard tribofilm during wear or scratch tests may have a significant influence on the wear process or fracture resistance. The microstructural description of the corrosion mechanisms were connected with microstructure changes analysis caused by the influence of the corrosive, aggressive bodily fluids like Ringer solution as well as with the analysis of chemical composition of the fluids after corrosion process. Acknowledgment: to 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 : Concept of multilayer design has been applied for deposition of superhard transition metal nitride coatings. Series of CrN/MoN films were fabricated by vacuum cathodic arc deposition under different predetermined values of nitrogen pressure, bias voltage applied to the substrate, and individual layer deposition time (thus, different individual layer thickness Λ in series). Each coating contains from 11 to 354 alternating layers with Λ from 1.5 μm to 20 nm. Characterisation of elemental composition, micro- and nanostructure by energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), including grazing incidence (GIXRD) and in-plane XRD, in a couple with physical and mechanical properties tests (microindentation, tribological test) gave a complex research, which allowed to study relations between deposition conditions, structure and exhibited properties of coatings. It was found that the preferential crystal growth orientation changes with increase of bias voltage absolute value. Decrease of nitrogen pressure in a chamber leads to the formation of β-Cr2N phase additional CrN and γ-Mo2N detected at pN = 0.4 Pa. The highest hardness end H/E ratio was registered for the samples with the thinnest layers among deposited ones (H/E = 0.11, 42 GPa when Λ = 20 nm).

Resume : PA6, as an aliphatic polyamide, has well-known strong hydrogen bonding capacity which affects its physical properties directly and try its best to bridge polyamide chains. When PA6 molecules are maximizing hydrogen bonding in crystalline region, the nylon 6 chains display two forms, α-phase and γ-phase, fully extended and twisted configuration. The previous work implied that α-phase has higher density H-bonds than γ-phase. Thus, α-phase is believed to be stronger than γ-phase, which results in the significant difference in mechanical properties of PA6. The crystallization of PA6 is affected very much by introducing the nucleating agent in the crystallization process. The microstructure of composite decides the crystallization behavior and its macroscopic properties obviously. To identify this problem, we introduce several kinds of nanocarbon to be nucleating agents in the crystallization of PA6.

Resume : We report the water contact angles (WCAs) of graphene oxide (GO)/acrylic and few-layered graphene (FLG)/acrylic nanocomposite coatings spin-coated on 3D-printed polylactic acid (PLA) surfaces. Our goal in this work is to improve the hydrolysis resistance of PLA (average WCA = 81.5º), a common plastic used in additive manufacturing, by coating with potential hydrophobic films based from low-cost commercial acrylic resin as matrix and graphene derivatives as filler. GO filler was synthesized from graphite by a one-step modified Hummer’s method, while FLG filler was prepared by liquid phase exfoliation using high-speed homogenization and probe ultrasonification of graphite in dimethylformamide solvent. Fillers were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy, atomic force microscopy, and X-ray diffraction. The addition of GO modified with stearic acid (3-5 wt% of GO) into acrylic resin at specified loadings (0.3 and 0.4 g GO per 5 ml acrylic resin) has negligible influence on the average WCA of unfilled acrylic coating (WCA = 64.4º). However, the addition of FLG (1.07 – 1.33 g FLG per 5 ml acrylic resin) dramatically increases the average WCA of acrylic coating by 57.8 – 73.6% (WCA = 101.6º – 111.7º). Average WCA of nanocomposite coating varies significantly with FLG loading, while the addition of stearic acid during FLG synthesis (1 wt% of graphite) has small effect. Weight change monitoring of samples during exposure in moist environment at 30ºC and 80% relative humidity for 96 h shows PLA with FLG/acrylic nanocomposite coating has higher hydrolysis resistance than bare PLA. The nanocomposite coating also retains its surface hydrophobicity after humid exposure.

Resume : Nitride semiconductors materials have attracted considerable interest for solar energy application and high speed electronics. More especially, Zn-IV-N2 is a new family of nitride semiconductor materials with great potential of applications for solar materials [1]. This work presents the development of ZnSnN2 thin films by reactive co-sputtering using zinc and tin metallic targets. The stoichiometry of the films was controlled by optimizing operating parameters such as the target voltage, the nitrogen partial pressure or the total pressure. The structure of the films was studied by X-ray diffraction. Although the deposition temperature was limited to the room temperature, the films show a highly crystallization level and a strong preferred orientation in the [001] direction. The microstructure was observed by transmission electron microscopy. The selected area electron diffraction (SAED) pattern shows the growth direction of thin film of ZnSnN2. 119Sn conversion electron Mössbauer spectroscopy gives us deeper information. The value of electrical resistivity at room temperature is 0.229 Ω cm. The electron concentration of ZnSnN2 thin film determined by Hall effect measurements is 1.0x1019 cm-3. The electron mobility value was 3.8 cm2 V-1s-1 References [1] A. Punya, et al. 2011 - physica status solidi (c)

Resume : We present the synthesis of reduced graphene oxide (rGO) and silver nanoparticle-reduced graphene oxide composite (Ag-rGO) using aqueous phytoextracts of Artemisia vulgaris (AV) and Psidium guajava (PG) as reducing agents. rGO samples are efficiently reduced with minimal damage to the crystal structure when refluxed for 6 hours as compared to 12 hours. In addition to de-oxygenation of graphene oxide (GO), the phytomolecules present in AV also functionalise graphene layers with electron withdrawing groups and results in multilayer restacking leading to the formation of hedgehog-like three dimensional nanostructures. As compared to AV, reduction of GO with PG extracts yielded rGO with good dispersibility in water. It is found that PG extract simultaneously reduces mixture of silver nitrate and GO solution which is confirmed by various spectroscopic techniques. Trace contaminants such as manganese derivatives present in the composite are probed for the first time via surface enhanced Raman scattering mechanism (SERS). rGO with different dosage of silver nanoparticles are prepared to examine its efficiency to detect Methylene Blue via SERS. The composite shows remarkable performance in detecting Methylene Blue with concentration as low as 100 nM and with an enhancement factor of 4.6 X 105. In addition, to detection of Methylene Blue via SERS based mechanism the composite has been employed as a photoluminescence turn-off sensor for the detection of Eriochrome Black T. The sensitivity of the probe is further tuned by activating the plasmonic field at 350 nm excitation which enhances exciton dissociation. The linear calibration plot for the intensity ratio was obtained with the optimised concentration of Eriochrome Black T between 0.1 µM and 7.5 µM. This composite material selectively detects Eriochrome Black T where detection limit as low as 10.5 µM is achieved.

Resume : The rapid advancement in the research of flat 2D nanomaterials, especially in graphene, the hexagonal monolayer of carbon (C), which can play the leading role due to its unparalleled physical and electronic properties. It has been proved that graphene can serve as a perfect 2D support for anchoring metal or metal oxide nanoparticles [1]. Anchoring metal oxides on graphene/gold hybrid electrode would enhance the electrochemical properties of material depending on its structure, size, and crystallinity. Exfoliated graphene sheets can be obtained from graphite and plasma deposition, they can form stable aqueous colloids through electrostatic stabilization [2]. Graphene–gold nanoparticles (AuNPs) hybrid can be fabricated by the reduction of HAuCl4 using hydrazine followed by sodium citrate [3]. Nano-sized oxide particles anchored on the surface of Graphene/AuNPs hybrid or wrapped within the hybrid could be synthesized using the synergistic effect acting between graphene and different metal oxides. When it is used for electrode materials, the graphene- AuNPs/ metal oxide composites, with which unique structural variables like anchored or wrapped, should have a substantial improvement in their electrochemical properties such as high specific capacity, high rate capability, high energy density and excellent cycling stability as compared to their individual constituents. Combined advantages of both graphene/AuNPs hybrid and metal oxides results in improving the electrochemical energy storage, lowering the current electrode problems of the individual components of graphene or metal oxides as active materials. References (1) Kamat, P. V. Graphene-Based Nanoarchitectures. Anchoring Semiconductor and Metal Nanoparticles on a Two-Dimensional Carbon Support. J. Phys. Chem. Lett. 2010, 1, 520–527. (2) Li, D.; Müller, M. B.; Gilje, S.; Kaner, R. B.; Wallace, G. G. Processable Aqueous Dispersions of Graphene Nanosheets. Nat. Nanotechnol. 2008, 3, 101–105. (3) Chen, Y.; Li, Y.; Sun, D.; Tian, D.; Zhang, J.; Zhu, J.-J. Fabrication of Gold Nanoparticles on Bilayer Graphene for Glucose Electrochemical Biosensing. J. Mater. Chem. 2011, 21, 7604.

Resume : N-doped graphitic carbon nanorods were synthesized by thermal transformation of zeolite imidazolate framework-8 (ZIF-8) nanorods. The morphology and pore structure of the carbon nanorods were readily tuned by using tri-block co-polymer Pluronic F127 as a soft template. The as-synthesized carbon nanorods exhibit an ultra-high surface area of up to 2088 m2 g-1, high N-dopping ratio and a bimodal distribution of pores on mesoporous and microporous structure. In addition, N-doping provides active sites for redox reaction that promotes electrochemical performance. Being used as an electrode material in a supercapacitor, the N-doped carbon nanorods render a high specific capacitance of up to 497 F g-1 at a current density of 0.5 A g-1. An ultra-long cycle life was also demonstrated by recording a 97.26% preservation of capacitance after 10000 cycles of charge-discharge at a current density of 4.0 A g-1.

Resume : The initial porous silicon (por-Si), carbonized porous silicon (por-Si:C) and carbon-incorporated porous silicon oxide (por-SiO2:C) layers were studied by electron paramagnetic resonance (EPR) at T=10-13 K. The initial por-Si samples were carbonized in N2/C2H2 flow at 850C and 1050C resulting in the formation of carbonized porous silicon (por-Si:C). The carbon-incorporated porous silicon oxide (por-SiO2:C) layers have been obtained by thermal treatment of the por-Si:C in moisturized argon flow at 700C. Two low-intensity signals of Lorentzian lineshape were detected in the EPR spectrum of por-Si, por-Si:C, por-SiO2:C layers. One of them was attributed to the Pb0 defect at the Si/SiO2 interface of nanocrystalline grain and second to the silicon dangling bonds (SiDB) localized in nanocrystalline Si. The carbonization of por-Si layers and subsequent oxidation of por-Si:C gives rise to the appearance of additional EPR signals of high intensity at g=2.0035(3) in por-Si:C and at g=2.0030(3) in por-SiO2:C, which were assigned with carbon-related defect (CRD) and carbon clusters, correspondingly. It was found that predominant defect types in por-Si:C and por-SiO2:C layers are CRD and carbon clusters, respectively, while the spin concentration of Pb0 interface defect and SiDB is low. The work was supported by Ministry of Education and Science of Ukraine (Project F2904), MEYS SAFMAT LM2015088 and LO1409 projects.

Resume : In the present work, optically transparent silica film with covalently bonded alizarin yellow (AY) was prepared using a novel sol-gel synthetic rote. It was found that AY attached to the silica framework through amide linkage retains the ability to respond on pH change by color transition. The pKa value of indicator dye moieties decreases from 10.9 to 5.5 at their covalent bonding with silica surface. Influence of b-cyclodextrin (b-CD) on pH-sensing properties of individual and grafted AY was evaluated by spectrophotometric titration in phosphate buffer solutions. It was found that phenolic hydroxyl groups of AY become more acidic in the presence of oligosaccharide (pKa decreases from 10.9 to 10.5). Contrariwise, the ionization of phenolic hydroxyl group in AY-containing silica film takes place at higher pH values at addition of b-CD (pKa increases from 5.5 to 5.9). Obtained results prove that at complex formation of individual AY with b-CD its phenolic hydroxyl groups stick out into aqueous medium through one of the two openings of cyclic oligosacharide cavity, whereas interaction of surface AY-containing groups with b-CD proceeds through inclusion of phenolic hydroxyl group in internal cavity and leads to the depression of its ionization. Prepared silica material can be considered as potential pH sensor to monitor environmental acidity or provide selective recognition of organic molecules capable of forming strong inclusion complexes with b-CD.

Resume : Magnetic metal nanoparticles attract a great interest both in the scientific point of view and in connection with possible applications. In this work, we report a simple, controllable and economic method of preparing carbon-encapsulated Ni nanoparticles by direct pyrolysis of polyacrylic acid resin (PAA) which is exchanged with Ni ions under an inert atmosphere. The weakly acidic cation exchange resin of polyacrylic acid is used as carbon precursors. D113 resin is a kind of weakly acidic polyacrylic acid resin (PAA) with large hole structure. It is prepared by the methacrylic acid and divinylbenzene which has high exchange capacity, quick exchange rate and chemical stability. Nickel nitrates serve as Ni precursors in the synthetic route. This method is versatile and facile operation and the formed metal nanoparticles are easily dispersed into matrix of carbonized PAA. The structure, morphology and magnetic properties are investigated by means of X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and vibrating sample magnetometry(VSM). The results show the particle size of nano nickel in Ni@C can be controlled by pyrolytic conditions; the particle size increases as the pyrolytic temperature and the holding time increase. Magnetic tests show that Ni@C-500 is superparamagnetic, while Ni@C-600, Ni@C-700 are ferromagnetic. The remanence and the coercivity at room temperature of Ni@C-600 and Ni@C-700 are higher than those of the massive nickel, while the saturation magnetization is lower than those of massive nickel.

Resume : Many unique properties of metal nanoparticles have made it widely used in magnetic materials, catalytic materials, medical materials and nanoscale devices. However, because of the smaller metal particles, its oxidation is enhanced, and nanoscale metals will burn themselves in the air and can not be used directly. In this study, weak acidic polyacrylic acid cation exchange resin (D113) was used as precursor of carbon. After being exchanged with Co two valence ion, the nano Co particles were uniformly dispersed in carbon matrix and carbon encapsulated materials. The research provides technical basis for low cost and easy control process. Carbon coated nano Co particles were prepared by pyrolysis of Co-exchanged resin(Co/D113) at 400 to 700℃. The TG results show that the thermal stability of Co/D113 is better than that of pure D113 resin. The XRD and TEM results reveal that the cobalt particles existed mainly in the form of fcc Co phase, and the particle size of nano-Co increase with the increase of pyrolytic temperature. The magnetic tests show that the coercivity (Hc) of the pyrolyzates obtained at 400 to 700℃ at room temperature are much higher than that of the corresponding bulk material, and the Hc value is influenced by the size of the nano particles. The saturation magnetizations (Ms) of all the pyrolyzates are lower than that of bulk material and increase with the increase of pyrolytic temperature.

Resume : ?-Silicon nitride submicron-rods and nanowires have been synthesized via the thermolysis and crystallization of Si(NH)2 prepared by liquid-liquid phase method. Si(NH)2 was stable up to 900? and decomposed to amorphous silicon nitride.The submicron-rods and nanowires grows on the surface of amorphous silicon nitride by gas phase at 1400-1600?. The Si3N4 submicron-rods formed consist of ?- Si3N4 are 100-130nm in height and 150-300nm in width and a variable lengths. Silicon nitride nanowires are 60-100nm in diameter.Silicon nitride in both rod and wires forms via vapor-solid mechanism.

Resume : The present work studies the internal stress assisted hydrogen and nitrogen diffusion in austenitic stainless steel (ASS) taking place during plasma nitriding using various mixtures of nitrogen and hydrogen. A systematic model for nitrogen transport in ASS that takes into account the hydrogen actions at steel surface and bulk, hydrogen and nitrogen adosbtion and diffusion with concentration dependent diffusion coefficient and stress interaction is proposed. It is shown, that the stress effect on the nitrogen flux should be considered in nitrided ASS because they are subjected to the large internal stress induced by the lattice expansion when hydrogen and nitrogen atoms intrude in the steel matrix. The variation of stress changes the diffusion force, which is the gradient of chemical potential, and affects the interstitials distribution and, consequently, have effects on the nitriding kinetics. Moreover, although these results are obtained from the ASS-nitrogen-hydrogen system, our conclusions can be extended to the diffusion problem of other interstitials in metal alloys. Finally, it was shown, that the addition of hydrogen in H2-N2 mixture flux with concentrations in the range ~ (30 ? 40) % enhances nitrogen penetration into steel due to the hydrogen actions at steel surface. The obtained theoretical results are qualitatively consistent with the available experimental data.

Resume : Silver and gold nanoparticles are well-known materials for plasmonic applications. However, the optical properties of these metals are strongly modified at high temperatures. To overcome this problem, metal nitrides (TiN and ZrN) are suitable materials for high temperature plasmonic applications. Recently, it has been demonstrated that the plasmonic response of TiN- and ZrN-based materials is tunable in the infrared region by addition of a third element [1]. This contribution aims to show the effect of Y addition on the optical and electrical properties of reactively co-sputtered (Zr,Y)N films. The maximal value of the Y/(Zr+Y) ratio has been limited to approx. 50 at. %. The progressive addition of Y atoms into the ZrN films does not induce any change in the film structure, but a linear increase of the lattice constant as a function of the Y content has been evidenced by X-ray diffraction. A drastic change of the electrical and optical behaviors has been observed when the Y content exceeds 30 at. %. At low Y content the films exhibit a metallic-like behavior with low electrical resistivity and a strong absorption band in the visible range while a semiconductor-like behavior is evidenced at high Y content (Arrhenius dependence of the electrical resistivity and transparent films). Finally, the evolution of the films’ optical properties as a function of the temperature in the 25-400 °C range has been studied. [1]C. Metaxa et al., ACS Appl. Mater. Interfaces 9 (2017) 10825

Resume : N-doped graphitic carbonsubmicrorods were synthesized by thermal transformation of zeolite imidazolate framework-8 (ZIF-8) submicrorods. The morphology and pore structure of the carbon submicrorods were readily tuned by using tri-block co-polymer Pluronic F127 as a soft template. The as-synthesized carbon submicrorods with morphology preserved derived from submicrorods of ZIF-8 comprise both micro- and meso-pores with high surface areas of over 1000 m2 g-1. In addition, nitrogen-doping in the carbon submicrorods was achieved as was confirmed by XPS and EELS. The hybrid carbon submicrorods provide pseudo-capacitance that promotes electrochemical performance, rendering a high specific capacitance of up to 297 F g-1 at a current density of 0.5 A g-1 in a three-electrode system. A long cycle life was also demonstrated by recording a 90.26% preservation of capacitance after 104 cycles of charge-discharge at a current density of 4.0 A g-1. Furthermore, a symmetrical supercapacitor is fabricated by employing the carbon submicrorods, which shows good electrochemical performance with respect to energy, power and cycle life.

Resume : Boron nitride (BN) is extremely attractive material due to its high thermal conductivity, low density, electrical insulation, inertness, etc. Similarity of graphitic carbon layers structure and hexagonal boron nitride layers stimulated the search for carbon-like BN nanostructures and, correspondingly, for new synthesis routes for nano-BN fabrication. Here we report on the direct catalyst-free synthesis of light-emitting nanoparticles of boron nitride. Nanoparticles were fabricated by heating of initial boron powders of different sizes in nitrogen flow. The synthesis was done in the optical furnace under the concentrated light of a xenon high-flux lamp. Structure, morphology and phase composition of the material obtained were characterized by electron microscopy and X-ray diffraction methods. Optical properties of nano-BN were characterized by photoluminescence method under band-to-band excitation conditions at room temperature. The BN nanoparticles synthesized demonstrate rather wide luminescence band in the UV spectral range. Comparison of the measured emission spectra with the ones of other nano-BN materials reveals the absence of the emission in violet-blue range in nano-BN grown in optical furnace. This finding demonstrates that content of deep light-emitting defects in the material obtained in optical furnace has lower as compared with the commercially available nano-BN, BN of turbostratic structure and BN of pyrolytic graphite structure.

Resume : With increasingly serious global energy and environmental problems, water splitting on TiO2- based photocatalysts for conversing solar energy to hydrogen has attracted great interests (T. Simon et al., Nat. Mater., 2014, 13, 1013). In particular, how to improve the efficiency of traditional TiO2 photocatalysts is an ongoing research spot. There are great efforts have been devoted to facilitate the TiO2 photoinduced electron-hole pair separation and improve the light harvesting such as by coupling with other semiconductor, depositing noble metals, doping with metals or nonmetal, and controlling crystallographic facets. More current evidence has illustrated that oxygen vacancies on TiO2 nanocatalyst could suppress the photoinduced electron-hole recombination and play an key role in enhancing photocatalytic activity (J. Li et al., Appl. Catal. B, 2017, 206, 300). According to Donnay-Harker rules, the surface free energy of the {001} facets (0.90 J/m2) is 2 times that of {101} ones (0.44 J/m2), implying much more reactive {001} facets than {101} ones of TiO2, thus possible endowing higher photocatalytic activity. Commonly, the nonmetal doping, especially N-doping has displayed great potential in enhancing photocatalytic activity of TiO2 (G. Liu et al., J. Am. Chem. Soc., 2009, 131, 12868). Therefore, it is highly desired to prepare novel O-vacancies-enriched N-doped anatase {001}TiO2 hierarchical structures for greatly improving the photocatalytic activity. However, the reported N-doped anatase TiO2 often using HF, an extremely corrosive contact poison, greatly restrict its application. Herein, a series of N-doped {001}TiO2 hierarchical nanosheets spheres Nx{001}TiO2-t (x = N/Ti = 0.11 and 0.27, feeding molar ratio; t = 12, 24 and 36 h, reaction time) have been first prepared by a moderate fluorine-free solvothermal method. The samples are carefully studied via XRD, Raman, SEM, (HR)TEM, BET, XPS, PL, ESR and PAS methods. The obtained hierarchical spheres are self-assembled by the ultrathin nanosheets (ca. 10 - 13 nm) consisting of ultrafine anatase nanocrystals (ca. 11 nm) and show uniform mesoporous distribution and high specific surface area. The N elements are successfully incorporated into both the substitutional (Ns) and interstitial (NI) sites of TiO2 lattice and the obtained high Ns/NI ratios imply the increasing amount of O-vacancies. All Nx{001}TiO2 catalysts show higher Ti3+/Ti4+ ratios than undoped {001}TiO2-24, corresponding to a large number of small neutral Ti3+−O vacancies, which is in favor of enhancing the photoinduced electron-hole separation. The photocatalytic H2 evolution activities for the series of Nx{001}TiO2-t catalysts (ca. 1.73 wt% Pt loaded as the co-catalyst) in methanol-H2O medium are obviously higher than undoped {001}TiO2-24 and P25. Especially, N0.11{001}TiO2-24 exhibits the highest H2 evolution rate of 23.8 mmol·h-1·g-1, and also shows considerably high H2 evolution rate of 11.8 mmol·h-1·g-1 in 5.35 M KOH, mainly attributed to its high exposure of {001} facets and enriched Ti3+-O vacancies upon from proper N doping, and its highest SBET (144 m2g-1). A possible photocatalytic mechanism of Ti3+-O vacancies-enriched N-doped {001}TiO2 mesoporous nanosheets spheres is tentatively proposed.

Resume : Under extreme heat fluxes due to ELM’s and plasma reaching the walls of the ITER fusion plasma reactor, vaporization and melting is most likely to occur. The behavior under extreme conditions of plasma facing components is of great interest. Tungsten (W), beryllium (Be) and carbon (C) and their mixtures need to be exposed and characterized mechanically and structurally. We present a new method which could be used in metallic thin film deposition. The method is based on the vaporization and ionization process of metal wires with microwave field. We used a 2.45 GHz frequency at 800 W microwave power source. A cylindrical cavity having the TM011 propagation mode accommodated a jigging device and the metallic wires were vaporized and ionized. The metallic wires used in this experiment were made of W, Be and C. The metallic wires having 0.5 mm diameter were vaporized and ionized in direct interaction with the microwave field from the cylindrical cavity. We investigate the dependence between the metal quantity which is vaporized and ionized by the microwave field and the microwave power. Electron temperature of metallic plasma produced using the microwave generator was estimated using the ratio of atomic emission lines acquired by a high definition optical multichannel spectrometer. Mechanical, tribological, as well as the crystallographic orientations and the grain size of the thin films deposited on silicon substrates were determined using nanoindentation, tribometry, X-ray diffraction at low angle, scanning and atomic force microscopy and were correlated with the processing parameters as microwave power, and the distance between the wire and the substrate holder.

Resume : The diffusion saturation of iron-based alloys with nitrogen and carbon is widely used in industry for increasing strength, hardness, wear and corrosion resistance of metal products operating in extreme environment. Inexhaustible and unrealized potentialities of such treatment are opened when applying it under strain and stress condition. The topical question in this direction is to clarify diffusion and strengthening mechanisms of strained alloys under chemical-thermal treatment by N and C. The effect of preliminary plastic deformation from 5 to 70 % with the step 5 and 10 % on nanostructured diffusion layers formation, kinetics of their growth, chemical and phase composition and microhardness was studied in Fe and iron-based (Fe-Cr, Fe-Ti, Fe-Cr-Ti, Fe-Ni) alloys doped with Cr, Ti or Ni in amount of (0.5 – 2.0 wt.%) after the saturation with nitrogen and carbon from a gas mixture of ammonia and propane-butane at 853 K for 0.5; 1; 2; 4; 6; 8 hours. As a result of the investigation, it was found that the diffusion layer is a combination of surface layers of different nanosized nitride and carbide phases, nanostructured eutectoid layer and a nanostructured zone of internal saturation. Deformation considerably effects on the phase formation, structure, microhardness and thickness of nitrided and carbide layers. Microhardness test of nitrided layers has discovered the narrow intervals of deformations of 3-8 % and 20-30 % in which the considerable rise (in about 2 times) of microhardness of surface diffusion layer in Fe after nitriding exist. The high microhardness of the diffusion layers results from the formation of nanosized nitrides and carbides. The concentration distribution of N and C and the depth of their penetration also depend on deformation degree and correlate with the microhardness test results. The possible mechanisms of diffusion and mass-transfer of interstitials (N and C) in deformed alloys are discussed and the possibilities of the interstitials mass-transfer with mobile dislocations in deformed alloys according to the dislocation-dynamic mechanism are especially considered.

Resume : LaCoO3 shows a metal-insulator transition associated to an interesting change in optical properties. Deposited on aluminum substrates, the material acts as a smart selective layer due to the variation of emissivity. LaCoO3 was synthetized by magnetron sputtering in order to make an easy upscaling and the temperature of metal-insulator transition (TMI) was lowered using nitrogen-doping in order to use it as a thermal-control coating on solar panels. A two-steps process was employed: the first step is the co-sputtering of cobalt and lanthanum in poisoned regime followed by a crystallization step in a furnace. Samples are characterized with a scanning electron microscope, X-ray diffraction, and secondary ion mass spectroscopy. The optical properties of the samples have been studied, using an infrared or UV-visible reflectance versus temperature to investigate their ability to regulate temperature. Transmission electron microscopy analysis shows a globular micro-structure. Crystallization’s kinetic has been studied by observing the evolution of (110) planes. Reflectivity versus temperature gives a variation of emissivity over 50% at lambda=8µm between 573K to 773K.

Resume : In recent years, fuel cells became one of the most attractive technology for energy conversion devices. The use of catalyst and more specifically platinum allows to increase the conversion rate. With the growing interest for these technologies the price of platinum increased and the resource depletion constrained to find an alternative way. One possibility is to develop a non-Pt material as catalyst. It has been shown that tungsten carbide presents the same electronic behavior as platinum but due to their ability to react with oxygen in air, carbides are easily oxidized. Depending on kind of synthesis methods and kind of oxygen occupied sites, catalyst effect on rates of reaction increases or decreases. It has been demonstrated that when oxygen atoms replace carbon atoms, that is upon the formation of tungsten oxycarbide, the catalytic activity is enhanced. Thin films of tungsten oxycarbide were grown by direct liquid injection CVD on silicon wafer covered by native oxide using tungsten hydride as precursor. A two steps process has been developed by depositing a dense tungsten oxycarbide layer on a porous tungsten oxide layer. Surface and cross-sectional morphologies obtained by SEM evidenced that porosity of the tungsten oxide layer is temperature dependent. However, oxycarbide deposits obtained at higher temperature on the oxide do not modify the porosity character. X-ray photoelectron spectra evidenced that oxycarbide deposit completely covers the tungsten oxide.

Resume : The aim of the research project is to test carbon aerogel functionalised carbon fibre (CAG-CF) electrodes in fuel cells and redox flow batteries. The drive to reduce global greenhouse gas emissions has resulted in alternative fuel vehicles coming to the forefront of clean energy as a means to reduce anthropogenic emissions. With this goal in mind, an important area of research is using new materials for alternative fuel systems that can improve their performance in order to compete with traditional internal combustion systems. The focus of this study will be on the use of spread-tow carbon fibre, which has been already been utilised in supercapacitors. Spread-tow can potentially offer a smaller, lighter and more efficient electrode construction compared to regular tow carbon fibre. The electrodes performance will be assessed for fuel cell and flow battery systems, comparing the material to those used for current electrodes, and any improvements they may offer, for example, higher efficiencies, weight/size reduction etc. The project will consist of material characterisation, mechanical and electrochemical properties testing and system tests.

Resume : The development of electronics and especially sensors puts increasing demands on new materials technologies. An example of such a challenge may be chemical or biological sensors, where e.g. electrical properties depend on the degree of adsorption of the chemical or biological substances. Materials that can be used in such applications are, for example conductive polymer composites with metal or carbon fillers. An advanced physical deposition method such as pulsed electron beam ablation (PED) is a promising alternative to both conventional deposition techniques and the laser-based processes for deposition of polymer thin films. The objective of the work was to deposit conductive thin films composed of PTFE/C composites using PED method. A target material was composed of PTFE matrix and different carbon fillers. The chemical structure of the polymer matrix was evaluated using Attenuated Total Reflection Fourier transformation infrared (ATR-FTIR) and X-ray photoelectron (XPS) spectroscopies. The carbon particles in the coatings were studied by Raman spectrometry and their distribution by high-resolution transmission electron microscopy. Electrical conductivity of thin films was also measured.

Resume : The reduction of reflection in visible light range, which is to increase the share of transmitted light, and to avoid the formation of ghost images in imaging is important for polymer eyeglasses lens application. In this study, the polymer eyeglasses lens of high refractive index, n=1.70, was fabricated by injection-moulding method with the polymer lens monomer, catalyst of dibutyltin dichloride, and releaser of isophorone diisocyanate mixture. To investigate the effective antireflective coating (ARC) structure, various ARC structures which including multi-layer ARC, tri-layer of discrete approximation of Gaussian gradient-index profile (Gaussian GI) ARC and tri-layer of conventional quarter-wavelength (QW) approximation ARC are designed and coated on fabricated polymer lenses by E-beam evaporation system. The optical properties of the polymer lenses were characterized by UV-visible spectrophotometer. The most effective ARC structures of the polymer lens with high refractive-index, n=1.70, is a tri-layer of Gaussian GI approximation ARC. The mean reflection of the Gaussian GI approximation ARD, multi-layer ARC, and QW approximation ARC in the range of 400 nm to 800 nm were measured to 2.2%, 3.2%, and 4.6%, respectively.

Resume : Pyrolysis of organometallic precursors of iron is an economical and versatile technique for the synthesis of carbonaceous materials of varying morphology. Multifunctional core-shell iron/iron carbide nanostructures encapsulated in carbon matrix were synthesized via fluidized bed one-step pyrolysis route using two different catalyst precursors (ferrocene and iron acetylacetonate) with toluene and melamine. Samples synthesized using ferrocene show Fe/Fe3C core particles within a mixture of globules and nanotubes, while those with iron acetylacetonate-toluene show predominant Fe3C phase and higher formation of nanotube. Nitrogen doped carbon structures increased the amorphous nature of the materials as compared to undoped samples. N atoms reside on the carbon shells and the core nanoparticles remain similar to undoped samples. Furthermore, N-doped carbon structures show enhanced catalytic properties for reduction of nitro derivatives of Schiff bases and water splitting in comparison to the undoped counterparts.

Resume : Highly nitrogen-doped carbon nanoparticles (NCNPs) have been synthesized by laser pyrolysis method, using a reactive mixture containing different carbon donors: acetylene, ethylene or volatile liquids as benzene, nitrogen and carbon donors: 1,3 diaminopropane or 1,2 diaminoethane, as well as ammonia (as nitrogen source). Furthermore, a combination of ethylene and ammonia at different percentages acts as laser energy transfer agent. Also, argon flows were used both as central gas flow confiner and as gas flows to clean windows. The elemental percentages were evaluated by XPS and EDX analyses and the experiments were driven in order to generate nanoparticles with a highly N content especially at the superficial zone. The nanopowder yield and the N percentage in carbonaceous powder are strongly dependent with the temperature in the reaction zone and its value is controlled externally by incident laser power, ammonia/ethylene flows and the synthesis pressure. The TEM and SEM images of NCNPs reveal round shape nanosized particles with 20 to 40 nm mean particle size and an interconnected hierarchical pore structure. The synthesized NCNPs were also characterized by Powder x-ray diffractometry (XRD), Raman Spectroscopy and Fourier transform infrared spectroscopy (FTIR). In proper conditions as synthesized nanopowders with a high specific surface area (up to 200 m2 g−1) were prepared.

Resume : In this study, we report on the influence of film thickness on the optical properties of highly oriented (002) GaN with different thicknesses deposited on Si(100) substrate by hollow-cathode plasma-assisted atomic layer deposition using trimethylgallium and ammonia as the gallium and nitrogen precursors, respectively. GIXRD analysis reveals that the crystalline quality of GaN films was improved with increasing thickness. It has been reported that the average strain in GaN thin films strongly correlates to the film thickness. Out-of-plane strain of the GaN films changes from tensile to compressive with increasing thickness whereas in-plane strain changes from compressive to tensile. The spectroscopic ellipsometry analysis reveals that optical film density and local crystallinity was improved with increasing film thickness to 48.65nm. The optical band edge results suggested that bandgap widening is valid for all GaN films. Phonon modes, free-carrier properties and mode broadening parameters which have information on the crystalline quality and compositional homogeneity have been studied by infrared reflection spectroscopic ellipsometry. It was observed that the LO mode positions change depending on the thickness. Moreover, free carrier effect was observed for films thicker than 48 nm.TO and LO-phonon-plasmon coupling modes of these films were examined in detail. The overall results suggested that GaN films with thicknesses above 48.65nm have different behavior compared to the thinner GaN films. Optical anisotropy of GaN films with different thickness have been studied by infrared spectroscopic ellipsometry. The lattice vibrations perpendicular and parallel to the optic c axis were expressed by Lorentz oscillator function model. It was found that the LO phonon frequencies changes with increasing thickness. The ordinary and extra ordinary dielectric functions of the GaN epilayers were also determined.

Resume : In the thin film preparation using a sputtering method, a high density solid target by a sintering method is generally used as a target to be a base material of the thin film. However, the organic materials, it is difficult to produce the sintered target because of its low melting point. On the other hand, several types of solid targets or compound targets are used for preparation a multi-element composite thin film composed of a plurality of elements. However, there is a problem that the apparatus is large in size, high in cost, and low in material usage efficiency. In order to solve the above problem, we propose the sputtering method that was used the powder target instead of the sintered target. In this study, we used (1) N-doped Ni powder which is a wide bandgap semiconductor, (2) Alq3 (tris (8-hydroxy-quinolinato) aluminium) powder target which is an organic EL material, (3) mixed powder target of oxide materials which is a functional material. We investigated the influence on the properties of the deposited films of the deposition conditions such as RF power and Ar gas pressure.

Resume : ZrCN and ZrCrSiCN coatings were deposited in an atmosphere of C2H2 and N2 on Si (100) and 316L steel substrates, using the cathodic vacuum arc technique. The coatings were grown at constant C2H2/N2 mass flow rate ratio, substrate bias and deposition temperature: ~0.80, -200 V and 3200C, respectively. The films were characterized in terms of elemental and phase composition, crystalline structure, hardness, reduced elastic modulus and adhesion. The corrosion resistance and tribological performance of both coatings in 3.5% NaCl solution were also investigated. Cr and Si addition to ZrCN coating leads to reduction of crystallite size, finer microstructure and lower hardness; the corrosion resistance and wear performance under corrosive testing conditions were enhanced. We discuss the mechanical and tribological properties of the two coatings in terms of hardness to reduced elastic modulus ratio. All coated samples exhibited high corrosion protection efficiency, reaching 97.8% for ZrCrSiCN coating. Both coatings improved the tribological performance of 316L steel in saline solution, for ZrCrSiCN coating being observed a 60% decrease of the wear rate. Summarizing, ZrCrSiCN coating represents a suitable protective coating for parts/mechanical components working under severe wear and corrosive conditions. We acknowledge the support of the Romanian National Authority for Scientific Research and Innovation, project no. 90PED/2017 and Core Programme 2018.

Resume : Nanoparticles are increasingly used as an alternative to antibiotics and can be used to prevent bacterial infections. In this paper, we report on the deposition of zinc oxide nanoparticles (ZnONPs) / organosilicon nanocomposites by using a planar, RF (13.56 MHz) atmospheric pressure cold plasma source. HMDSO vapors are introduced in the remote discharge by means of an atomizer system working under continuous argon flow, leading to deposition of thin layers of organosilicon matrix in which ZnO is embedded. The deposition of ZnONPs is accomplished by spreading a mixture of ZnONPs and ethyl alcohol by means of an ultrasonic vibrated nozzle which sweep the surface where was deposited the first layer of HMDSO. The uniform spreading of ZnO nanoparticles into the nanocomposite layers was confirmed by Scanning electron microscope (SEM) and Energy dispersive X- ray spectroscopy (EDX). The evolution of chemical composition of the obtained nanocomposites upon the deposition parameters was investigated. The surface composition as revealed by XPS investigation show concentration of 13.58% silicon, 31.15% oxygen, 1.19% zinc and 54.08% carbon.The antibacterial activity and cytotoxic properties of the samples (ZnONPs) against Escherichia coli and Staphylococcus aureus were studied. This work has been financed by the Romanian Ministry of Research and Innovation in the frame of Nucleus programme - 2018 and PlasmaTex M-ERA-NET contract 31/2016.

Resume : The growth of cubic GaN layers on (113) and (001) oriented GaAs substrates were investigated by metal organic vapor phase epitaxy (MOVPE). The growth of low temperature GaN nucleation layers (500-550 °C) was in-situ monitored by laser reflectometry (LR). The simulation of experimental reflectivity curves, by using an optical model which includes both time-dependent growth rate and surface roughness profiles, shows differences between growth kinetics depending on substrate orientation. Thus, growth anisotropy was observed. The effect of high temperature (750-900 °C) GaN sublayers grown on 130 nm thick GaN buffer layer deposited on (113) GaAs substrate at low temperature (550 °C) was analyzed. The GaN sublayers were ex situ characterized by scanning electron microscope (SEM), high resolution X-ray diffraction (HRXRD) and room temperature cathodoluminescence (RT-CL). Based on comparative study between structural and optical qualities of GaN layers grown on the two substrate orientations, we conclude that the crystalline structure strongly depends on both temperature and substrate orientation. The SEM micrographs and 2?/? spectra showed that the (113) oriented GaAs promotes the alignment of cubic GaN (113) columns at a growth temperature close to 850°C. For this temperature, the RT-CL spectra exhibited only cubic GaN emission (3.23eV) for the two orientations (001) and (113) of GaAs substrate. Keywords: MOVPE, c-GaN(113), GaAs(113) substrate, HRXRD, Cathodoluminescence.

Resume : Dilute bismide-nitride compound GaNAsBi is a promising candidate for use in GaAs-based optoelectronics devices in the near-infrared region. In this work, we report results of the electronic band structure of GaNAsBi/GaAs strained multiple quantum wells (MQWs). The band structure was modeled within the 16-band anti-crossing model, envelop function formalism and Bir-Pikus theory in conjugation with k·p Hamiltonian method. This investigation was used to describe the optoelectronics properties behavior of these structures such as band offsets, subband energies, strength of inter-band transitions and absorption coefficient spectra. We show that absorption coefficient spectra of GaN.04As.91Bi.05/GaAs strained single QWs has two maxima respectively located at 5,24 104 cm-1 for ?_(e1-hh1) and 6, 37 104 cm-1 for? ??_(e1-lh1). In addition, we have presented the results of the GaNAsBi-based strained double QWs (DQWs). We have deduced that the combined effects of strained and coupling between two wells enhance considerably the absorption coefficient compared to uncoupled DQWs. Keywords GaNAsBi-based strained QWs, Double QWs and coupling, Bir-Pikus theory, Absorption coefficient Optoelectronics properties

Resume : We have been researching so-called gliding arc discharge (GAD) for a long time. There has been interest in the use of GAD system for various applications in material processing, nano-particles formation, surface treatment, gas decomposition, water treatment, biological disinfection, plasma agriculture and environmental protection. The advantage of GAD is generated on discharge possibility in atmospheric pressure condition with a cheap commercial power supply without a vacuum system. In addition, from a diagnosis of GAD mechanism, we proposed serpentine plasma as a name of the discharge plasma. In this study, nanoparticles preparation using this GAD was carried out. The advantage that nano materials can prepare by atmospheric pressure is great. On the other hand, because large flow quantity of a gas (1 -40 L/min) is required on GAD, we should pay attention to utilization efficiency of gas. In this paper, methane (CH4) diluted argon (Ar) was used as source gas. 1 - 5minutes discharge time was used. Nano materials were prepared on a silicon substrate. The substrate temperature was controlled from room temperature to 600 °C. Our GAD system used a low-pressure mercury lamp as UV source of which the photon energy for the main spectrum is about 5 eV for ignition. High voltage (sine wave, 60 Hz) was applied between two electrodes with a high-voltage transformer. Waveforms of applied voltage and discharge current were measured with a high-voltage probe (Tektronix, P6015A) and a current clamp (Tektronix, TCP2020), respectively. Both waveforms were captured with a digital oscilloscope (Lecroy WaveRunner 204Xi-A). Time-resolved digital photographs for plasmas were recorded by a high-speed digital camera (Nobby Tech. Ltd., Phantom V.1210) with the frame rate of 20,000 frames per second. The nano particles were analyzed by Electron Beam 3D surface roughness analyzer with EDX-EDS. As a result of SEM measurement, nanoparticles were confirmed. The average diameter of a particle was divided into three categories as followings. Those are 180 nm, 45 nm and 15 nm group. The generation of nanoparticles and/or the thin films was controlled by substrate temperature. As a result of the XPS measurement, as for the binding energy of the nano particle, it was confirmed that C-C binding. It was carbon except for the element of the silicon substrate by a result of the EDS measurement.

Resume : In the present work, we prepared palladium-nickel/reduced graphene oxide RGO/PdNi nanocomposites by chemical reflux method and then disperse in Ethylene-vinyl acetate (EVA) polymer by solution mixing method to achieve the improved thermal, mechanical and EMI shielding performance. Phase, morphology, bonding interaction and chemical state of RGO/PdNi nanocomposite and its RGO/PdNi/EVA nanocomposite thin films were studied by using XRD, SEM, TEM, AFM, XPS, Raman and FTIR techniques. It was observed that 1wt\% RGO/PdNi/EVA nanocomposite possess maximum improved tensile strength (~139%), elongation at break (~52%) and toughness (~111), while young modulus (~101%) was maximum of 0.5 with% RGO/PdNi/EVA nanocomposite as compared to neat EVA. Thermogravimetric studies showed that incorporation of RGO/PdNi into EVA polymer matrix increases the thermal stability compared with neat EVA. Further investigations showed the significant enhancement in the total shielding efficiency RGO/PdNi/EVA-5 (~22 dB) compared to neat EVA (~4 dB) at 2 GHz. It could be expected that this perspective would be helpful for fabricating many other carbon based alloy/polymer nanocomposites for their potential in electromagnetic interference (EMI) shielding applications.

Resume : Biomaterials are widely used in repair, replacement of diseased or damaged parts of the musculoskeletal system such as joints. As a consequence, the material and the tissue environment should coexist without posing undesirable/ inappropriate effects on each other, so ensuring a long service. (Zr,Ti)CN coatings, with different non-metal/metal ratio were deposited by DC magnetron sputtering on Ti6Al4V alloy and Si substrates, and investigated as possible candidates to be used as protective layers for joint implants. The films were analyzed for elemental and phase composition, crystallographic structure, mechanical properties, corrosion behavior, surface wettability and cell viability. The coatings were found to have composite structures, in which a (Zr,Ti)CN crystalline phase coexists with an amorphous a-C(N) one. Film thickness and hardness in the ranges 1.8–2.1 microns and 25–29 GPa, respectively, were measured. The coated samples exhibited an improved corrosion resistance as compared with the bare alloy. Both coating types were found to be hydrophobic, the contact angles being higher than 100°. Cell viability measurements proved that the osteosarcoma cells are adherent to the coating surface, the highest viability (90.5%) after one week incubation being found for the film with high non-metal contents. We acknowledge the support of the Romanian National Authority for Scientific Research and Innovation, project no. 90PED/2017 and Core Program 2018.

Resume : Indium nitride (InN) is a small band-gap semiconductor material which has potential application in light-emitting diodes, high performance high electron mobility transistors and high efficiency solar cells due to its superior properties such as high absorption coefficient, high electron mobility and small electron effective mass. For specific applications, these properties could be optimized by alloying InN with other metal nitrides. In this work we studied the influence of yttrium addition to InN thin film and explored the possibility to engineer the electrical, optical and structural properties of resulting material. Single-phase YxIn1-xN layers with low concentration of yttrium were deposited by reactive radio-frequency magnetron sputtering method on Si(100) substrates at 500 ºC. On the investigated compositional range, 0 ≤ x ≤ 0.14, the wurtzite structure of InN was preserved and the InN-YN alloying led to the increasing of the lattice parameters, electron mobility and optical band gap values. The electron mobility presented the largest tunability range varying from about 248 cm2/V/s (x =0) to about 1513 cm2/V/s (x = 1.14). We acknowledge the support of the Romanian Ministry of Research and Innovation through the National Core Project.

Resume : TiSiC coatings alloyed with stainless steel (TiSiC-SS) were deposited on Si (100) and C45 steel substrates using the cathodic arc method with TiSi alloy and stainless steel cathodes in C2H2 atmosphere. The carbon content in the coatings was varied from approximately 41 to 64 at. % through changes of C2H2 flow rate and arc current at the stainless steel cathode. The coatings were investigated for elemental and phase composition, chemical bonding state, crystalline structure, morphology, hardness, adhesion strength, friction and wear performance. The coatings were found to possess a composite structure consisting of crystalline metallic carbide and amorphous free carbon. For carbon content higher than 43 at. %, the coatings exhibited a poor crystallinity and a random texture. All deposited coatings showed compact cross-sectional morphologies. It has been shown that the friction and wear performance of the coatings were strongly dependent on the carbon content, the coatings with C/metal ratio higher than unity had clearly superior tribological characteristics compared to the coatings with C/metal ≤1. Depending on the carbon content, different wear mechanisms were identified: adhesive and oxidative wear for the coatings with C/metal ≤1, and polishing wear for C/metal >1. Among the coatings, those containing the highest carbon content of ~ 64 at. % provided the best wear resistance (wear rate of 1.1×10-6 mm3N-1m-1) and the lowest friction (coefficient of friction of 0.15). We acknowledge the support of the Romanian National Authority for Scientific Research and Innovation, project no. PN-III-P1-1.2-PCCDI2017-0239 and Core Programme 2018.

Resume : This study aims in developing carbon-based amorphous films with embedded metallic nanoparticles of controlled size and atomic content. More precisely, a custom-made hybrid (PVD/CVD) system is used to deposit hydrogenated amorphous carbon (a-C:H) films with various contents of embedded metallic (silver or titanium) nanoinclusions. The film thickness and surface topography were quantified using X-ray reflectivity and atomic force microscopy measurements. The bonding characteristics of the deposited films where probed using Raman spectroscopy, whereas microstructural details were investigated using scanning and transmission electron microcopy. Thin films on the order of ~100nm with metallic nanoinclusions (4-10nm) were deposited with sub-nanometer surface roughness characteristics. The nanoscratch resistance of the nanocomposite films was found to increase with the metal content, as measured using the three-pass nanoscratch method. It was observed that the metallic nanoparticles possess a spherical shape and retain their chemistry within the a-C:H matrix, i.e., neither Ag nor Ti generate any bonds with the surrounding matrix, as evidenced by high magnification TEM images. The scratch enhancements were found to relate to (a) the reduction in the residual compressive stresses induced by the metal-induced graphitization of the a-C:H matrix, (b) the ductility enhancement of the a-C:H matrix and (c) to the nanocomposite nature. The enhancements induced by the metallic nanoparticles coupled with the very low friction coefficient of these material systems (<0.05) establish them as excellent candidates for a variety of protective coating or solid lubricant applications.

Resume : The need of more performant integrated circuits and high power density communication devices drives the development of materials enhancing the conductive performances by carbon nanoparticles. Among nanocomposites, the ternary hybrid carbon nanotubes/graphene nanoplatelets/polymer composites represent a debatable route to enhance the transport performances. Polymer composites with various carbon inclusions like multiwalled carbon nanotubes (MWCNT), carbon black (CB), graphite or graphene are interesting for fundamental research and are attractive for various applications [1]. The electrical percolation threshold of these composites could be very low and it is important to obtain as low percolation threshold as possible in order to reach optimal mechanical properties of composites and to use minimal concentration of expensive fillers. Adding several different fillers in the matrix the percolation threshold can decrease in comparison with single filler composites due to synergy effect between the different components [2]. In this contribution the dielectric/electrical properties of epoxy resin composites filled MWCNT, GNP and hybrid MWCNT/GNP filler with total contents 0.3 wt.% at different ratios were investigated. The properties of composites and synergy effect will be presented and discussed in wide frequency and temperature range. References 1. W. Bauhofer, J. Z. Kovacs, Composite science and technology 69, 1486 (2009). 2. J. Chen, X. Ch. Du, W. B. Zhang, J. H. Yang, N. Zhang, T. Huang, Y. Wang, Composite science and technology 81, 1-8 (2013).

Resume : New fast and low-cost methods based on electrical discharges in liquids are intensively studied for the preparation of bimetallic and alloyed metal particles. In general, to obtain composite NPs the following techniques can be applied: chemical co-reduction method, laser ablation, electrodeposition, co-sputtering technique and combined approaches. However, the preparation of the homogeneous alloy targets with high yields favorable for practical applications, especially from bulk immiscible metals, remains very challenging. In this context, the development of new approaches seems to be an essential alternative. The capabilities of submerged arc discharge in liquids offer the possibility to synthesize original nanoparticles (core-shell structures, wires, 2D nano-objects, etc.). Combined with post-synthesis laser induced modification opens up the way to new possibilities. The low mutual solubility of Ag with Cu makes the synthesis of AgCu alloys by conventional methods operating under thermodynamic equilibrium conditions very challenging. We report the successful preparation of alloyed near-spherical AgCu nanoparticles using a two-step technique based on electrical discharge processing of the mixture of Ag and Cu micropowders with subsequent ns laser irradiation of the formed colloid. The formation of alloyed AgCu nanocrystals is proved by the results of UV-Vis spectroscopy, EDX and HRTEM measurements.

Resume : Lithium-ion batteries have attracted many attention for use in portable electronics applications owing to their high energy density. However, the low cyclability and the pulverization of the electrode originating from volume change during the lithiation/delithiation processes greatly restrict their applications. In order to improve the cycling stability of lithium-ion batteries, tremendous research efforts have been devoted to analyzing their electrode materials, morphologies and hybrid with carbon composites. Herein, we successively synthesized hierarchical multi-shelled zinc cobalt oxide hollow nanospheres coated with N-doped carbon via facile three-step processes. The voids and spaces between neighboring shells of zinc cobalt oxide and carbon cloth can effectively buffer the volume expansion of active materials during lithiation/delithiation processes, and the electrically conductive carbon material can promote the fast electron transfer.

Resume : Luminescent carbon nanomaterials, especially for carbon nanodots, have attracted much attention due to their unique properties, such as low toxicity and high luminescent efficiency. In this paper, we report on a novel approach in which carbon nanodots can be directly grown on Si-based substrates without any metal catalysis . It is clarified by combining Raman, Atomic Force Microscope (AFM), and X-ray photoelectron spectroscopy (XPS) measurements that the carbon nanodots with the controlled diameters are uniformly distributed on the substrates. Photoluminescence (PL) measurement reveal that the carbon nanodots feature a sharp blue light emission. The PL peak position is almost independent of the nanodot size. This suggests that the photoluminescence of carbon nanodots should not originate from quantum confinement effect but from the surface effect of nanodots. Our work provides a promising simple approach to obtain luminescent carbon nanodot for practical applications.

Resume : In this work, we propose to develop a new type of semi-conductor structure that can be implemented in the photoanode of dye-sensitized solar cells (DSSCs): anatase/rutile bi-layered N-doped TiO2. We investigated the synthesis of this material by two different ways: co-Reactive Magnetron Sputtering in Ar/O2/N2 mixture; and combination of RMS (Ar/O2 mixture) and Nitrogen Ions Implantation (NII). For the co-RMS method, our strategy consists on a systematic evaluation of the influence of the sputtering gas composition on the crystalline, the chemical and the optical properties of the films. For the hybrid method, our strategy consists first on optimizing the titania bi-layered crystalline structure by playing on the plasma discharge. Then, a systematic evaluation of the ion beam parameters such as the dose, the ion energy and the incident angle was performed in order to study the implantation spot and the properties of the films. Preliminary data reveal that the bi-layered crystalline structure cannot be obtained by co-RMS but we demonstrated that N atoms position can be easily controlled, promoting their insertion at substitutional sites into the TiO2 lattice by tunning the gas mixture. Using NII, as expected, the concentration and the position of the N atoms mainly depend on the ion dose and energy. Based on the results, we finally conclude that ion implantation leads to very low nitrogen content (≤ 1%) while co-RMS tends to synthesize oxynitride films (3% ≤ [N] ≤ 14%).

Resume : We present a simple and facile method for preparation of carbon-like polymeric nanospheres via morphological stabilization and transcription of beta-lactoglobulin (ßlg). This globular protein spontaneously self-assemble to soluble spherical aggregate (ca. 80-300 nm) upon heat treatment at definite pH. Our approach involves the construction of π-conjugated co-polymer coating around the outer surface of protein spheres. Here we used for the first time, 1,5- dihydroxynapthalene and 1,3,5-trimethyl-1,3,5-triazinane for surface modification of ßlg amphiphilic protein, which crosslinked on the protein surface with extension of π-conjugated structures by in situ co-polymerization at room temperature (298 K). Further the obtained core-shell structure composed of π-conjugated polymer-coated ßlg protein sphere was transformed to hollow carbon nanosphere with tailored properties by carbonization at moderate temperature. The hollow spheres were characterized by using transmission electron microscopy (TEM). The cross sectional analysis with field emission scanning electron microscopy (FE SEM) of core-shell structure revealed polymer coating on the ßlg protein surface. The obtained conjugated polymer and carbon hollow sphere were further characterized by energy dispersive x-ray spectroscopy (EDS), solid state NMR, dynamic light scattering (DLS). The surface properties of prepared organic and carbon nanosphere can be adjusted by hybridization of different types of functional materials and provides interesting platform for nanoarchitectonics.

Resume : The metal oxide thin films including vanadium dioxide and tin oxides have been researched as a functional material for thermochromic applications and environmental gas detection such as NO2, CO, CH4, H2, and EtOH. The vapour transport method is one of the commonly employed synthesis method of nanostructured materials. The tin oxide exhibits various morphologies which are nano-belts, nano-slabs, nano-disks, and nano-branch depending on growth condition. In this study, vanadium dioxide and the tin oxide nanostructures are grown using a two-zone thermal chemical vapour deposition system. The source material, vanadium dioxide or tin dioxide powder (Sigma-Aldrich, purity: 99.9%) was vaporized in an alumina crucible. The flow rate of carrier gas Ar(purity: 99.999%) was 200 ~ 1000 SCCM. The vanadium dioxide and tin oxide nano-structures were grown on graphene nanosheets/SiO2(300 nm)/Si substrates. The graphene nanosheets were grown on Cu foils by thermal CVD method with the CH4 and H2 gas. The quality of synthesized graphene nanosheets, as-grown vanadium dioxide and tin oxide nanostructures were investigated by Raman spectroscopy. The morphology and crystallographic properties of as-grown vanadium dioxide and tin oxide nanostructures were characterized by FE-SEM, FE-TEM, and XRD, respectively.

Resume : Highly oriented (Ti,Al)N films with a very low level of impurities are necessary to investigate its local strain evolution and defect structure during spinodal decomposition. In this study, heteroepitaxial c-(Ti0.38,Al0.62)N thin films are grown on MgO (001) and MgO (111) substrates using reactive magnetron sputtering. XRD reciprocal space maps show that the films are epi-layers with homogenous strain. The high-angle annular dark-field scanning TEM images show coherency between the film and the substrate. Corresponding geometric phase analysis (GPA) deformation maps show a high stress field in the as-deposited state. At elevated temperature, the films decompose to form coherent AlN- and TiN- rich domains with elongated shape along the elastically soft <100> direction. GPA analysis reveals that the number of dislocations in the film decreases and the TiN domains accommodate more dislocations than the AlN domains. The stronger directionality of the covalent chemical bonds in AlN compared to TiN makes it more favorable for the dislocations to accumulate in TiN. The chemical bonding state and elastic properties are governing factors in determining the defect structure of (Ti,Al)N during spinodal decomposition, which also affect its mechanical behavior.

Resume : Thanks to their unique set of features such as fast read/write speed, very high scalability, excellent endurance, good data retention and multi-level storage capability, phase-change (PC) memories are now considered as one of the best candidates for the next generation of non-volatile memory (NVM) [1]. PC memories rely on the fast and reversible transition between amorphous and crystalline states of a phase-change material (PCM) and to the resulting huge contrast of optical and electrical properties. PCM are mainly based on Ge-Sb-Te chalcogenide alloys already used for long-time in optical data storage. Nevertheless, PC memory technology still has to overcome several challenges to definitively invade the NVM market, and more particular decreasing the switching energy [1]. In that context, we will show how C introduction can enhance the properties of the 2 prototypical alloys GeTe and Ge2Sb2Te5 (GST) such as improving data retention as well as decreasing the programming currents of PC memory [2]. The impact of C on the structure and properties of GeTe thin films will be investigated by means of atomic and nano-scale structural investigations. Finally, we will show how the introduction of C nano-layers in PCM by means of magnetron sputtering of amorphous GeTe (GST)/C super-lattices would permit to tailor and improve further the properties of PCM thin films. [1] Noé P. et al. Semicond. Sci. Technol. 33, 013002 (2018). [2] Noé P. and Hippert F., Structure and Properties of Chalcogenide Materials for PCM in Redaelli A. (eds), Phase Change Memory, Springer, Cham (2018).

Resume : In the quest of designing low cost noble-metal-free catalysts, iron-iron carbide (Fe/Fe3C) has been demonstrated as a versatile and robust material. These heterogeneous structures also find usage in magnetic devices and biomedicine. Graphitic encasing enhances the properties as well as acts as an effective protective layer. Pyrolysis of organometallic precursors of iron is a simple and cost-effective technique for the synthesis of such carbonaceous materials. In this regard, multifunctional core-shell iron/iron carbide nanostructures encapsulated in carbon matrix were synthesized via fluidized bed single-step pyrolysis route using two different catalyst precursors (ferrocene and iron acetylacetonate) with toluene. The variation of phase composition and morphology of the materials was studied by a variety of characterization techniques. It was also observed that a low heating rate lead to a globular morphology while a high heating rate favoured the formation of carbon nanotubes. The samples synthesized using ferrocene-toluene show a complex structure comprising four prominent iron-containing phases: α-Fe, γ-Fe, Fe3C and paramagnetic Fe-C inclusions. In contrast, samples synthesized using iron acetylacetonate-toluene show predominant Fe3C phase. Thus, under controlled synthesis conditions, the type of catalyst can lead to variable phase composition in Fe/Fe3C-graphite systems, which in turn greatly influences the properties of the material. Nitrogen doping of these carbon structures increased the amorphous nature of the materials. It was observed that N atoms exclusively attach with the carbon shells and the core nanoparticle remains the same as in case of undoped samples. Furthermore, N-doped carbon structures show enhanced hydrogen evolution under controlled conditions and increased catalytic reduction of 4-nitrophenol to 4-aminophenol, as compared to the undoped counterparts.

Resume : Antibacterial surfaces are rapidly emerging as a primary component of the global mitigation strategy of bacterial pathogens, because this is highly efficient method for prevention of so-called nosocomial (hospital-acquired) infections.. There are three major strategies for designing antibacterial coatings: antibacterial agent release, contact-killing, and anti-adhesion/bacteria-repelling. In the last few decades, attention was drawn to different nanomaterials (nanoparticles, nanofibers, nanotubes) for its usage in smart drug delivery, tissue engineering and other biomedical applications. Nanomaterials can be a perfect drug carrier as well as a matrix supporting cell adhesion and proliferation. For example, biodegradable polycaprolactone (PCL) nanofibers due to their outstanding properties [1]. However, PCL as hydrophobic polyester has limited use, especially in a predominantly hydrophilic bioenvironment for tissue engineering. Its modification with hydrophilic synthetic and bio-polymers opens new horizons for its applications . It should be noted that this material is not sufficiently suitable for maintaining cell adhesion, proliferation, and differentiation, due to the hydrophobic nature of its surface. This drawback can be overcome by surface modification of PCL nanofibers leading to increasing biocompatibility of the material. Recently we have found that COOH plasma modification can enable immobilization of antimicrobial agents on the surface of nanomaterial, but it is no sufficient to significantly enhance the cell adhesion and proliferation. We have proposed the strategy based on the immobilization of the Platelet-rich Plasma (PRP) onto modified PCL nanofibers. Our strategy allowed to boost the cell adhesion and proliferation. The summary of our most recent results will be presented in the talk.