ALTECH 2020 - analytical techniques for precise characterization of nano materials

Resume : Historically, optical imaging formation relies on the possibility of collecting light scattered/diffracted by an object to reconstruct an intensity distribution able to provide information about the object spatial distribution. This holds particularly for objects exhibiting a refractive index very close to that one of the external environment, such as cells or thin slabs of organic tissues. In an attempt to increase the image contrast, several methods has been proposed in the past, including staining and fluorescence tagging. However, these approaches require the sample to be altered, often in an non-reversible way, by means of more or less complicated (bio)-chemical processing. On the other hand, label-free techniques and more specifically, Quantitative Phase Imaging (QPI), offer the advantage of being used without a specific preparation of the sample, thus allowing for example, the observation of living matter without significant drawbacks on the sample health. In this perspective, a QPI technique called Gradient Light Interference Microscopy (GLIM) is presented . This technique can be implemented on standard optical microscopes as it relies on Differential Interference Contrast (DIC) imaging that is conventionally used in biology and material science. The GLIM technique is shown as a fast and effective way to have a direct mapping of the phase gradient associated to a transparent sample by exploiting low-coherent polychromatic light that is typically available in any microscope. Examples of realistic complex samples such as collagen fibrils and cells will be provided and commented.

Resume : Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy that achieves a spatial resolution below 20 nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties (dielectric function) of the sample directly below the tip, yielding nanoscale resolved optical images simultaneous to topography or local spectroscopic information about a specimens reflectivity and absorption [1,2]. In latest s-SNOM applications, the combined analysis of complex nanoscale material systems by correlating near-field IR spectra with information obtained in a wider spectral range (VIS to THz frequencies) has gained significant interest. For example, the material-characteristic nano-FTIR spectra measured for nanoscale Acetaminophen (Paracetamol) particles can be directly compared with nanoscale resolved tip-enhanced Raman spectrum (TERS) obtained on the very same sample location. Further, correlative measurements of the near-field optical response of semiconducting samples like Graphene (2D) or functional SRAM devices (3D) and Kelvin Probe Force Microscopy (KPFM) measurements reveal complementary quantitative information about the local conductivity in engineered nanostructures. As a result, s-SNOM systems have the potential to characterize complex material systems by different near-field and AFM-based methods at the nanoscale for a wide range of different applications. [1] F. Keilmann, R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, 787 (2004). [2] F. Huth, et al., Nano Lett. 12, 3973 (2012).

Resume : In recent years, we have come to appreciate the astounding intricacy of the processes leading to the formation of minerals from ions in aqueous solutions. The original, and rather naive, ‘textbook’ image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. Does it, however, mean that all the minerals grow through intermediate phases, following a non-classical pathway? In general, the precursor or intermediate species constitute different, often short-lived, points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/total scattering) appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathway because of the temporal and spatial length scales that can be directly accessed with these techniques. In this presentation we show how we used scattering to probe the crystallisation mechanisms of calcium sulfate, This system contains minerals that are widespread in diverse natural environments, but they are also important in various industrial settings . Our data demonstrate that calcium sulfate precipitation involves formation and aggregation of sub-3 nm anisotropic primary species. The actual crystallisation and formation of imperfect single crystals of calcium sulfate phases, takes place from the inside of the initial aggregates. Hence, calcium sulfate follows a non-classical pathway.

Resume : Ternary oxides have become valuable layer materials with manifold applications spanning from display technology and photovoltaics to low-E IR protection coatings. Mixed oxides based on tin (Sn) and zinc (Zn) have attracted attention as they avoid the supply problem associated with indium. In this presentation, we present work on the properties of SnxZnyOz mixed oxide layers. These layers are produced by means of a co-sputtering process involving two different targets with varying plasma power properties. The layers were investigated with spectroscopic ellipsometry to determine their thickness and dielectric function. The optical properties thus obtained are strongly correlated with the electrical conductivity of the layers, transparency, composition and electronic state of the metals. By using a combination of different analytic techniques, we can improve coating processes and find optimal combinations of material properties for different applications.

Resume : Surface-functionalized organic, inorganic, and hybrid nanoparticles (NP) are of great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. NP performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Methods for FG quantification should be simple, robust, reliable, fast, and inexpensive, and allow for the characterization of a broad variety of nanomaterials differing in size, chemical composition, and optical properties. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG such as amine1,2, carboxy1,2, thiol and aldehyde3 functionalities, we designed a catch-and-release assay utilizing cleavable probes that enable the quantification of the cleaved-off reporters in the supernatant after particle separation, and thus, circumvent interferences resulting from particle light scattering and sample-inherent absorption or emission.1 Moreover, the cleavable probes allow for a complete mass balance by determining the particle-bound labels, the unbound reporters in the supernatant, the reporters cleaved off from the particles, and the groups remaining on the particle surface after cleavage. The potential of our cleavable probes for the quantification of carboxy and amino groups was demonstrated for commercial and custom-made polymer and mesoporous silica particles of varying FG densities, underlining the benefit of the catch-and-release assays as a versatile method for the FG quantification on all types of transparent, scattering, absorbing and/or fluorescent particles.1,2 Our catch-and release assay concept also allows for the determination of the relative FG orientation on micellar encapsulated quantum dots.4 In the future, our cleavable probe strategy can be easily adapted to other analytical techniques requiring different reporters, or to different types of linkers that can be cleaved thermally, photochemically, or by pH, utilizing well-established chemistry, e.g. from drug delivery systems. References. (1) M. Moser, N. Nirmalananthan, T. Behnke, D. Geißler, U. Resch-Genger, Anal. Chem. 2018, 90, 5887-5895. (2) N. Nirmalananthan-Budau, B. Rühle, D. Geißler, M. Moser, C. Kläber, A. Schäfer, U. Resch-Genger Sci. Rep. 2019, 9, 17577-17587. (3) A. Roloff, N. Nirmalananthan-Budau, B. Rühle, H. Borcherding, T. Thiele, U. Schedler, U. Resch-Genger, Anal. Chem. 2019, 91, 8827-8834. (4) D. Geißler, M. Wegmann, N. Nirmalananthan-Budau, U. Resch-Genger, “Quantification of functional groups and determination of their relative orientation on micellar encapsulated quantum dots”, manuscript in preparation.

Resume : Elemental depth distribution is nano-engineered in the materials designed for advanced microelectronic and optoelectronic components. Knowing the chemical composition of near-surface and in-depth nanostructured materials at each processing step is thus critical to develop and tune process parameters that will lead to best final device performance. Plasma profiling time-of-flight mass spectrometry (PP-TOFMS) is a rapid chemical nano resolution depth profiling technique. The fast erosion rate of the glow discharge plasma and the high-speed time of flight mass spectrometer are combined to make PP-TOFMS a suitable tool for giving fast answers to process (growth, etching) developers and thereby accelerate deployment of innovative materials. In addition to speed, other characteristics of the technique such as calibration free semi-quantification, full element coverage and easy operation contribute to make PP-TOFMS an in-line metrology tool. We will illustrate such close to process advantages for nitride materials for light emitting diodes and power electronics. For the latter, a fast feedback on the Al, In, and Ga contents has been key to understand the incorporation of unintentional gallium and design the appropriate reactor configuration and conditions. The example of surface stoichiometric modifications of GeSbTe alloys developed for phase change memories upon etching and other patterning steps will also be shown. In this case PP-TOFMS analysis comes in complement to XPS to provide in-depth information, both leading to best choice of plasma chemistry. The depth profiles of active GeSn layers for MIR optoelectronics will be presented as the Sn content in SiGeSn layer affects the carrier confinement and thus lasing performance.

Resume : The trend in miniaturisation of devices is increasing the need for characterisation techniques that are capable of investigating objects in 3D at nanoscale with both structural and chemical information. In this context, we have developed a Secondary Ion Mass Spectrometry (SIMS) system and coupled it to an Orion NanoFab Helium Ion Microscope (HIM). In the standard HIM mode, the instrument provides secondary electron (SE) images with a sub-nm lateral resolution. These high-resolution SE images can be correlated with sub-15 nm resolution SIMS images to gain access to the nanoscale composition of the investigated samples. This two-dimensional correlative microscopy approach has been extended to three dimensions by creating 3D representations of nanomaterials and overlaying the SIMS acquisition onto the 3D SE representation. Therefore, photogrammetry is used i.e. the sample stage is tilted and SE images are taken at specific rotation angles with a He+ primary beam around the region of interest (ROI). The SIMS images are acquired of the ROI in-situ at normal incidence with a Ne+ primary beam and projected then onto the 3D photogrammetry representation using correspondence points. In this presentation, we will show step-by-step the workflow for 3D reconstruction and SIMS correlation for nanomaterial applications to illustrate the potential of this method for a variety of different fields. [1] T. Wirtz et al., Annu. Rev. Anal. Chem. 2019. 12:523–43.

Resume : During solution growth of crystalline silicon from an amorphous seed layer, the crystallization dynamics was up to now only observable by time consuming and destructive methods like TEM. Raman spectroscopy allows for the discrimination between amorphous and crystalline phases of substances. We have developed a Raman mapping method for the fast and non-destructive characterization of an evolving crystalline matrix within the amorphous silicon. With dwell times of just 1 s, large areas can be characterized quickly without drift of the spectrometer. Thus, all data are gained with comparable calibration and a crystallinity figure of merit can be introduced to account for signal shift and signal intensity. With a time series of otherwise identical growth runs we reveal how nanocrystalline structures evolve during the growth process. The morphology of the seed layer influences the surface morphology of the final polycrystalline Si layer strongly. The prepared Si layers serve as absorbers for novel, cost-efficient solar cell layouts.

Resume : Perovskite solar cells (PSC) have demonstrated high efficiencies in recent years, with good scalability potential. The introduction of tandem devices with a perovskite top layer on silicon is also an exciting concept which has dominated record efficiencies for non-concentrator PV devices. Despite these promising aspects, stability issues are a significant obstacle for PSC to compete with established PV technologies. There are several critical factors for PSC degradation, and ageing tests require accurate environmental controls in order to distinguish different degradation mechanisms. This work presents in situ photoluminescence (PL) imaging as a tool to study the performance degradation of PSC. Using bespoke environmental chambers and ageing system developed at NPL, key environmental conditions such as atmospheric composition, spectrum and intensity of illumination, and temperature are accurately controlled for degradation tests. PL imaging provides spatial information on the initiation, propagation and classification of defects, and their correlation with current-voltage (I-V) curves. Through PL imaging and parallel I-V curve acquisition, it is demonstrated that material degradation develops around defects accompanied by a corresponding loss of short-circuit current, while the open-circuit voltage of the PSC sample is minimally affected. These analyses open a route to rapid non-contact screening of samples for removal of potential early failures and process optimisation.

Resume : Since the introduction of three-dimensional device structures such as the fin field effect transistor (finFET), the implementation of fast, in-line metrology aimed at the electrical characterization of such features has become challenging. Recently, the fully in-line micro four-point probe (µ4PP) technique has shown its capability to directly measure the resistance of nanometer-wide lines [1,2] . However, extracting the resistivity from the measured resistance requires the precise knowledge of the sample geometry, which is typically obtained from destructive and time-consuming cross-sectional Transmission Electron Microscopy (TEM) imaging. In this paper, we demonstrate an approach for extracting the resistivity of both Front-End-Of-Line (FEOL) and Back-End-Of-Line (BEOL) structures by using the Thermal Coefficient of Resistance (TCR) method [3] with µ4pp, i.e. measuring the dependence of the line resistance as a function of a varying current . To validate the technique, we show that the measured resistivity is identical on metal lines of slightly different geometries (i.e. different measured resistances), as should be expected. Finally, we study the impact of width on the resistivity of both metallic and semiconducting materials lines. [1] J. Bogdanowicz, et. al., 2018, Phys. Stat. Sol. (a), 215, 1700857 [2] S. Folkersma, et. al., 2018, Beil. Jour. of Nanotech., 9, 1863–1867. [3] C.E. Schuster, et. al., 2018, Microelectron. Reliab., 41, 239

Resume : A system to make external control electron beam was designed and implemented on the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Popular and cost-effective Arduino board was used to interface the microscope and hardware control, and the computer hosts the beam control with simple graphic-user-interface while collecting position-specific physical properties. The system was applied to 2-dimensional mapping of non-biased electron-beam induced current imaging and acquisition of spectrum-image cathodoluminescence signals in SEM and TEM. In this presentation, detail steps to build the system will be explained and possible expansion for the simple in-situ experiment will be discussed. Application results from TEM and SEM will be discussed – identification of preferential current paths from non-biased EBIC system and the diffusion length was measured from the GaN/InGaN multi-quantum well (MQW) LEDs. From the results of cathodoluminescence, it was found that the dislocations penetrating MQW tends to make blue shift in luminescence, and distributions on non-uniform optical band-gap with two distinct energies of 2.76 and 2.94 eV.

Resume : Nowadays an extraordinary control over the growth of nanowires (NWs) has been achieved, enabling also the integration of different types of heterostructures, which can lead to the engineering of the functional properties of the NWs. One of the many applications of NWs includes energy conversion. In this work, thermal characterization of Ge and Si allotrope heterostructured NWs is done using 3w-SThM. These NWs are composed of successive hexagonal 2H and cubic diamond 3C crystal phases along the <111> axis and are embedded in a silica matrix. The thermal characterization of these NWs revealed a strong diameter dependent decrease in the thermal conductivity, which can be predominantly ascribed to boundary scattering. In addition, we have also studied the effect of the phase transformation temperature, which influences the size and the number of 2H domains, on the NW thermal conductivity. We have deduced the NW thermal conductivity for different annealing temperatures and we have evidenced that this latter can constitute an efficient parameter to tune the thermal conductivity. During the final presentation, I will present these two studies but also the influence of doping on the thermal conductivity. These results constitute the first experimental evidence of thermal conductivity reduction in such allotrope 2H/3C heterostructured NWs.

Resume : Femtosecond pump-probe technics are a powerful way to probe ultrafast heat transfers in noble metals at the nanoscale. When an ultra-short laser pulse is absorbed, it generates a time-dependent heat flux at the sample surface, the electrons reach a temperature (Te) much higher than the lattice which remains close to room temperature, generating a transient non equilibrium state. Te can be monitored by measuring the related changes of optical properties through the relative variations of the reflected probe intensity. The key issue is to determine, at subpicosecond time scale, the thermoreflectance coefficient which relates the reflected intensity variations with Te. Furthermore, this coefficient has been widely considered as a specific constant for each material resulting in a large underestimation of the temperature. Recently a temperature dependence of the thermoreflectance coefficient was shown[1], but still tough to measure at these time scales. We will present a method to quantify this coefficient during the ultrafast heating and electron-phonon non equilibrium. We will demonstrate its nonlinear dependence with the temperature and its consequences. We are now able to perform “hot electrons” temperature measurements, converting our femtosecond pump-probe experiment in an ultrafast nanothermometer. These technics open the way to real time temperature mapping of nanostructures such as tapers and nanowires[2]. References: [1] T. Favaloro, J.-H. Bahk, and A. Shakouri. Characterization of the temperature dependence of the thermoreflectance coefficient for conductive thin films. Review of Scientific Instruments 86, 024903 (2015) [2] Lozan, O., Sundararaman, R., Ea-Kim, B. et al. Increased rise time of electron temperature during adiabatic plasmon focusing. Nat Commun 8, 1656 (2017)

Resume : In the present study, pH sensitive multifunctional polymeric nanocomposite coatings were developed and characterized. Towards this direction, titanium nanotubes (TNTs) were synthesized, loaded with dodecylamine (DOC) and were then reinforced into epoxy matrix to develop polymeric based nanocomposite coatings. Structural and morphological analyses were conducted using X-ray diffraction (XRD), scanning electron microscope (SEM) and transition electron microscope (TEM) techniques respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) techniques were used to confirm the loading of DOC into TNTs. UV-Vis spectroscopic technique was used to study the self-release of DOC in response to the pH change. It is noticed that time dependence self-release of DOC is sensitive to the pH of the corrosive environment. The electrochemical impedance spectroscopy (EIS) results indicate that the developed nanocomposite coatings demonstrate superior corrosion resistance at pH 2 as compared to pH 5. The improved corrosion resistive properties of nanocomposite coatings at pH 2 can be attributed to the more efficient release of DOC from the nanocontainers due to higher sensitivity towards acidic medium.

Resume : Single-molecule techniques have attracted great attention due to their ability to study and manipulate objects down to nano-scale while the behaviour of a specific molecule of interest is able to be addressed. The importance of these techniques is that they provide the opportunity for scientists to extract rich information and observe dynamic processes of individual molecules rather than conventional ways of averaging the ensemble. Although such techniques can achieve high spatial resolution, it commonly lacks sufficient temporal resolution, which is an obstacle in real-time observation of biomolecular dynamics, particularly for transient intermediates. This project aims to overcome this challenge by combining ultrafast spectroscopy with a single-molecule probe based on a dual-barrel nanopipette tunnelling sensor. The device is synthesised via laser-pulling dual-barrel nanopipettes before carbon filling, followed by gold deposition process. Then stability and functionality of the tunnelling junction created in the device is characterised electrochemically. Optical measurements are carried out to test the photocurrent of the device. Taken together, the results should illustrate the feasibility of conducting a time-resolved single-molecule sensing technique with high spatial resolution. Experiments on application with detecting molecules could be carried out if possible.

Resume : Gas sensing is a very vital and commonly adapted process in various industries and service sectors. The gas sensing can be as mundane as pressure leak in an automotive tyre to as critical as a flammable, hazardous or even toxic gas in environments where they find a huge requirement such as industries or in hospitals. It is highly crucial to detect the leakage of gases in these environments to maintain operability of some systems or prevent catastrophic incidents in others. A variety of gas sensors have been developed to sense these gases present either individually or as mixture with other gases. The reliability of a gas sensor is highly dependent on the gas sensor calibrating or testing chamber. The credibility of the gas sensing chamber would dictate the gas sensors performance. A gas sensor needs to be observed or characterized for its characteristic such as sensitivity, selectivity, temperature dependent response variation, sensing accuracy and precision, repeatability, response towards the exposed gas, response time etc. These characteristics can be accurately studied only when the behavioural characteristics of the gas chamber is predetermined and well characterized. The paper intends to propose a flow metric based gas sensing chamber as against the conventional volumetric chamber and analyses the flow nature in the chamber. The chamber is designed with single inlet port and single exhaust vent or outlet port. The placement of the substrate holder with respect to the chamber dimensions, flow characteristics in the chamber has been optimized to provide a laminar flow over the substrate which would result in higher sensing ability of the gas sensor. The paper also deals with the boundary layer suppression to provide maximal gas flow over the substrate, thereby enhancing the chance of sensing by the gas sensor. An integrated heater is also provided below the substrate holder which would be required due to the fact that some gas sensors operate at high temperatures for their optimal performance. Study on heat propagation from the heater onto the substrate holder is also involved. The flow characteristics of the entire chamber was analysed especially at the inlet port, over the substrate and at the outlet port. The paper focuses on complete modelling of gas sensing chamber, fluid dynamic studies of gas flow inside the chamber, optimal placement of substrate, optimal angling of the substrate facing the gas flow and the heat propagation from the heater onto the substrate holder.

Resume : Recently it was demonstrated that a stress biased [0 1 1] cut relaxor ferroelectric Pb(In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal can generate reversible strain >0.35% at low field of order 0.1MV/m[1], which was attributed to an interferroelectric phase transition marked by a sharp jump in strain. These high levels of strain are ?captured? by applying a modest mechanical compressive stress to the sample whilst exciting it electrically, which drives the ferroelectric rhombohedral FR - ferroelectric orthorhombic FO phase transition in these domain engineered relaxor ferroelectric single crystals. The nature of the transition under both stress and E-field was explored for Pb(In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3)O3-PbTiO3, at the XMaS offline x-ray laboratory source, ESRF, Grenoble, France. Electric field and stress was applied to the sample using a novel stress rig purposely designed to fit the diffractometer. Stress, field, charge, electric polarisation and strain were all measured in operando. Preliminary results will be presented showing the evolution of the complex phase transitions which highlights the requirement to perform in operando metrology. This work was funded through the European Metrology Research Programme (EMRP) Project Grant Number: 16ENG06 ADVENT, and ONRG - NICOP Project Number: N62909-18-1-2008 Electrosciences Ltd. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Resume : Cu-Fe-O thin films were co-sputtered from metallic Cu and Fe targets in the presence of a reactive argon and oxygen gas mixture. Evolution of the coatings composition as a function of the discharge current dissipated on each target allowed to obtain convenient composition. The influence of annealing temperature under vacuum and air atmosphere on physico-chemical properties of the films was investigated. The elaborated films were annealed at 380°C, 450°C and 550°C under vacuum and air atmosphere to achieve delafossite structure. The X-ray diffraction analysis revealed the presence of CuFeO2 with a preferred orientation along (006) plane. CuFe2O4 and CuO as the secondary phases were detected. Electrical properties have been investigated by ac impedance spectroscopy over a wide range of temperature up to 873 K starting from room temperature in the frequency range 5Hz–13MHz. The complex impedance plots display one semicircle with equivalent circuit functions as typical parallel RC. The analysis of conductivity indicates that both AC and DC conductivities of materials increase with increasing temperature. The activation energy values calculated from DC conductivity and angular frequency relaxation are almost identical, indicating that the conduction mechanism was thermally activated and was assured by hopping between localized states.

Resume : Tin antimony sulfide Sn-Sb-S (TAS) thin films were deposited on glass and Si substrates using vacuum evaporation technique. Spectroscopic ellipsometry (SE) is a non-destructive method that we used to study the optical properties of the films. The SE measured data were analyzed by considering double layer optical model for all the samples, with the two Tauc-Lorentz oscillators and Gaussian dispersion relations. From the ellipsometric study, we extracted the thickness, absorption coefficient, band gap energy, refractive index and extinction coefficient of all samples. All the films exhibited high absorption coefficient a in the visible range (>105 cm-1). The values of the band gap energy Eg of Sn-Sb-S thin films deposited on glass varied from 1.13 to 1.48 eV. For the samples deposited on silicon, the band gap energy Eg varied from 1.44 to 1.72 eV. The spectral dependencies of the refractive index and the extinction coefficient of Sn-Sb-S thin films were determined and analyzed.

Resume : Carbon materials are very useful for a number of applications. However, the possible presence of foreign species such as transition metals, originating from the synthesis or processing steps, is often overlooked. This is particularly relevant when studying powders of these materials. For instance, the extent to which these foreign species alter the electrochemical profile of carbons and affect their performance (in energy storage and conversion systems) is still not fully recognized. Molten salt oxidation (or fusion) is a promising approach to analyse the chemical composition of carbon materials via, for instance, the spectral analysis of their plasmas. Here, three commercial carbon powders, relevant for electrochemical applications, were selected to evaluate the versatility of fusion as a pre-treatment process for elemental analysis with inductively coupled plasma optical emission spectroscopy (ICP-OES). The interaction of the flux, a lithium borate salt, with the carbons was investigated following the examination of their post-fusion residues. For the three carbons, the degree of structural degradation varied. Generally, the doping with Li and/or B (whether substitutional or interstitial) was low to non-existent.

Resume : The on demand pattern generation on a substrate using phase separation in blend polymer mixture finds a broad spectrum of applications like fabrication of self-cleaning and super-hydrophobic surfaces, robust membrane materials etc. In the present study, a simple and novel technique for the generation of complex patterns was demonstrated using polymer-polymer bilayer system supported over silicon wafer. There is a strong evidence that the nature of a labile under-layer polymer affects the phase separation of the bilayer and the overall morphology. For instance, when a blend of polystyrene (PS)-polymethyl methacrylate (PMMA) in toluene was spun coat over thin layers of PMMA, blend or random block copolymer, no phase inversion was observed up on thermal annealing. However, the phase inversion took place in the case when the PS-PMMA blend was spun coat on PS (h ~ 50 nm) and then thermally annealed. Arguably, the surface energy of the polymer present in the bottom layer strongly affects the phase inversion in the blend top layer. Later, by selective solvent etching fascinating patterns were generated as characterized by atomic force microscopy. This providing the generic guidelines for complex pattern generation using different polymer combinations with distinct functionalities.

Resume : The emergence of 5th Generation (5G) telecommunications the Internet of Things (IoT) with 50 billion connected devices will strongly increase the demand for energy due to the continuous power consumption of the electronic devices needed to deliver these technologies. Improvement of the energy efficiency of devices and processes is therefore a key component for sustainable development of future products. Due to restrictions in current scaling strategies and dramatic thermal issues (particularly in wireless systems), semiconductor and electronics industries require the introduction of novel materials, more complete component characterisation and more efficient power management at the system level that will lead to the development of novel ultra-low power devices. To support industry in facing these challenging issues the European project in Metrology ADVENT aims to establish a robust metrology framework for in-situ, in-operando and Multiphysics characterisation of advanced materials and components, and for reliable and accurate data for an efficient power management system. This talk will provide an overview of the top - down approach proposed in ADVENT to improve energy efficiency at every development stage of future electronic products: system, component and material. A special focus will be given on material and component challenges for the next generation of electronic devices required in 5G and IoT applications.

Resume : Nanoindentation is the most popular method for the measurement of hardness and elastic modulus of nanoscale materials, such as thin films, nanocomposites and other nanostructured materials. The correct evaluation depends crucially on the correct evaluation of the so-called area function, which depends on the shape of the indenter tip. For many applications at the nanoscale, it is desirable to measure at very low contact depths which requires precise knowledge of the area function even at very shallow depths. Unlike the standard method for area function calibration using a reference sample, the direct measurement of the tip shape using atomic force microscopy and coordinate metrology offers full information about the shape as well as traceability. Although the idea of the procedure is simple and well-known, details of the measurement process and the evaluation are rarely discussed. In this contribution we present approaches and recommendations to the measurement and evaluation of the tip shape. Experimental settings, their effect on the measured data and appropriate corrections of will be discussed. The combination of AFM and coordinate measurement instruments will be addressed. Sources of uncertainties will be analyzed and evaluated, the uncertainty budget will be modelled using Monte Carlo simulations.

Resume : The bismide GaAs1-xBix alloy has experienced an extensive amount of research and represents the emerging class of bismuth-based III-V semiconductors. It is a promising candidate for multijunction solar cells applications, infrared lasers, and photodetectors. In this study, we synthesize nominally 1.0 eV bandgap bulk GaAs1-xBix layers aimed at photovoltaic applications and investigate the structure-property relationships of this material. Solid-source molecular-beam epitaxy is used to grow the bismides on flat and low-angle offcut (001) GaAs and Ge substrates. Scanning-transmission electron microscopy techniques are employed to elucidate the modes of Bi distribution in several distinct samples. Atomic-resolution high-angle annular dark-field imaging and numerical quantification using scattering cross-sections are employed to analyze atomically-abrupt GaAs-GaAsBi interfaces and the onset of CuPt-type ordering. The analysis is also performed on GaAsBi antiphase boundaries showing the distribution of various point defects. We use atomically-resolved X-ray energy dispersive spectroscopy to quantify the CuPt order-parameter and to chemically map Bi in the vertical composition modulation grown GaAsBi sample. Monochromated electron energy-loss spectroscopy is employed to measure bulk plasmon energy shifts in phase-separated domains, indicating the strain-state changes in this alloy. Photo-luminescence, X-ray diffraction, and charge-carrier lifetime measurements are also presented to provide a comprehensive picture of the alloys properties and its potential in photovoltaics.

Resume : The present trend of electronic miniaturization manifests in rather smaller devices, in which heat distribution could become a limiting factor. Therefore, heat transfer processes in micro- and nanoscale devices in the field of energy applications as well as thermoelectric materials have gained continuously rising interest over the past decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method to analyse local thermal conductivities of layers with thicknesses ranging from several nm to µm. In this work we investigate the SThM method applied to ultrathin films by performing 2D and 3D finite element method (FEM) simulations using the software tool COMSOL® Multiphysics (CM). The focus of the simulations is to explore the limits of SThM regarding materials such as hexagonal Boron Nitride (h-BN) and gain new insights into the heat transfer of ultrathin films. Therefore, we investigated the cantilever used by means of scanning electron microscopy (SEM) and transferred the cantilever geometry to CM. Step by step we simulated the displacement of the cantilever, the mechanical contact area between tip and sample and finally the heat transfer process between tip and the ultrathin film. Also, practical SThM measurements of ultrathin films are then compared to the theoretical FEM simulations. The simulations provide new insights into the heat transfer process of the SThM method applied to ultrathin films below 20 nm and reasonable meshing strategies.

Resume : It has long been recognized that Li-ion batteries do not perform well at low temperatures, which presents a significant barrier to their application in the electric vehicle and aerospace industries. However, a fundamental understanding of the temperature dependence of the lithiation-induced phase transitions and electrochemical performance of electrode materials remains lacking. In this study, we discover a distinct and unusual temperature dependence in the phase transition of anatase TiO2 nanoparticles on dynamic Li+ intercalation, with a decrease in temperature resulting in the formation of a supersaturated solid solution phase. Thermodynamic analyses show that the supersaturated phase is more stable at low temperatures. Further kinetic analyses reveal that Li redistribution is facilitated at high temperatures while limited at low temperatures due to the sluggish Li transportation across the electrolyte-electrode interface. This difference manifests as a thermodynamically-controlled particle-to-particle phase separation at high temperatures and a kinetically-controlled formation of a supersaturated solid solution phase at low temperatures. Enhancing the interfacial kinetics and interconnectivity of the active materials proves to be an effective means of weakening the dependence of phase transitions on temperature and facilitating phase separation, resulting in improved electrochemical performance at low temperatures. This study provides, for the first time, a comprehensive and in-depth understanding of the temperature dependence of the lithiation-induced phase transition in many-particle intercalation electrodes, which has important implications for the development of the next generation of all-climate rechargeable batteries.

Resume : The Scanning Microwave Microscope (SMM) consists of an atomic force microscope (AFM) interfaced with a vector network analyzer (VNA) operating at GHz frequencies. This non-destructive quantitative technique is currently used to determine electrical properties of nano-sized electronics devices or nanomaterials such as semiconductor thin films and nanowires, high-permittivity dielectrics, graphene and 2D materials, etc, through local impedance measurements. Here we present quantitative permittivity measurements on different dielectric materials. The traceability to the International System of units (SI) is realized by applying a modified Short Open Load (SOL) calibration method for the one-port VNA using three known capacitance standards. These three standards are established from a calibration kit composed of a large number of Metal-Oxide-Semiconductor (MOS) micrometer-sized capacitors fabricated on a single chip with capacitance values C ranging from 0.1 fF to 10 fF. Gold circular electrodes of different diameters have been deposited on the dielectric thin films under study to define capacitances to be measured by the calibrated SMM. The “unknown” dielectric samples are placed close to the calibration kit so that the SMM calibration data are preserved. A complete uncertainty budget is established leading to a combined type uncertainty of about 10 % in relative value (one standard deviation) on the measured permittivity values.

Resume : The interaction between the CdAs2 semiconductor and the ferromagnet MnAs was investigated in the concentration range up to 60 mol% MnAs. Liquidus lines were created. It was shown that between the semiconductor and the ferromagnet the eutectic is forming with coordinates - 6 mol% MnAs and Tm=614 °C. The liquidus lines temperatures, according to the data of melting effects, turned out to be higher than according to crystallization effects. This is due to the tendency for cadmium diarsenide vitrification. MnAs solubility in CdAs2 was ? 1 mol%. Magnetic properties measurements show that CdAs2 - MnAs alloys are ferromagnets (Tc=315 K). The magnetization in them increased with the MnAs content rise. For quenched samples with sizes of ferromagnetic inclusions ? 40 nm, a negative magnetoresistance effect of 2-3 % in the saturation magnetic field is characteristic. This is interesting for CdAs2 with MnAs magnetically granular structures based alloys creation. These data supplemented by the differential scanning calorimetry results. The thermal effect of the conversion from tetragonal (ferromagnetic) to hexagonal (paramagnetic) MnAs modification was observed in the samples. The temperature of the effects correlates with the data for the Tc determination from magnetic measurements.

Resume : The miniaturization processes involved in the semiconductor industry and in nanostructured device fabrication requires the parallel implementation of suitable standards for the dimensional characterization of structures having a minimum features size at sub-10 nm level. Therefore, new types of reference samples for traceable measurement are needed for length metrology at the nanoscale. In this context one interesting solution in order to satisfy this lack is represented by the directed self-assembly (DSA) of block copolymers (BCPs) combining top-down approach of conventional lithographic techniques with bottom-up BCPs capability to phase separate into high density features of different shapes at the nanometric scale. Recently we have demonstrated that the possibility to carefully tune the characteristic dimensions of the nano-domains confined inside periodic gratings, allows envisioning a strategy to use the DSA of BCP as a tool for the fabrication of lateral length standards. List of references: 1. ACS Appl. Mater. Interfaces, 9 (18), 15685–15697, 2017

Resume : The demand for further improvement in the field of label-free biosensing is one of the most crucial topics of life science nowadays. For this purpose numerous optical methods and combined techniques have been developed and new sensing structures have also been introduced in the last couple of years. One of the most widespread methods is the surface plasmon resonance (SPR) spectroscopy which utilizes the evanescent electromagnetic field as a sensing probe in liquid ambient. This evanescent field emerges from the coupled incident light and the collective electron oscillation on the surface of a thin metallic layer. Combining SPR with spectroscopic ellipsometry is a common technique that has several advantages, e.g. the detection of the phase information leads to an enhanced sensitivity. Other possible improvement is the utilization of new materials or layer systems, e.g. using a Ag layer instead of Au, since Ag has more favorable properties regarding the biosensing purposes. Other materials and metal alloys have also been introduced as promising plasmonic metarials. In this study a novel layer system is presented consisting of an alloy layer of Ag and Al and also a SiO2 waveguide layer on top of it. The alloy layer was realized with the so-called combinatorial sputtering technique that makes possible that all the possible composition values of the two materials (from 100% Ag to 100% Al, with linear change along the sample) are presented only on one sample. Subsequently the biosensing properties of this layer are demonstrated by a combined SPR-SE measurement of a protein adsorption process. (OTKA K131515, OTKA K129009 and M-ERA.NET VOC-Detect projects is greatly acknowledged.)

Resume : Fluorescence chemosensors based on organic ionophores have long been investigated as a selective and sensitive method of monitoring various metal ions. Immobilisation of these molecules onto optical fibres has also emerged as an avenue for efficient, real-time sensing of metal ions, suitable for in-situ measurement. Surface-functionalization of exposed-core optical fibres has successfully been used to develop optical probes for certain metal ions.[1,2] However, a key issue remains the reliable and efficiency surface-functionalization of silica. We present a new fluorescence Li+-sensing platform based on a single-step functionalization of silica glass with a novel dye. The dye is based on a naphthalene diimide core and an aza-crown-ether ionophore, displaying altered absorbance and “turn-on” fluorescence in the presence of Li+ in solution and on grafting to silica. [3] Functionalization of the dye with a trialkoxysilane group enabled covalent grafting to silica in a single step without pre-treatment of the surface. This is the first example of single-step surface functionalization of silica using any kind of fluoroionophore. This system has potential biological application and is currently targeted towards making in-situ measurements of [Li+] in battery electrolytes. [1] Ruan, S. et al. Meas. J. Int. Meas. Confed. 121, 122–126 (2018). [2] Bachhuka, A. et al. Sensors (Switzerland) 19, 1–8 (2019). [3] Hangarge, R. V. et al. ChemistrySelect 2, 11487–11491 (2017).

Resume : Combining Grazing Incidence X-Ray Fluorescence (GIXRF) and X-Ray Reflectometry (XRR) is gaining increasing interest for the accurate and precise characterization of innovative materials with structures at the nanometer scale. CASTOR is a goniometer dedicated to this technique, which is currently used on the METROLOGIE beamline of the SOLEIL Synchrotron [1]. CASTOR can be installed on both branches of the beamline: the XUV branch (45 eV – 1.9 keV) and the hard X-ray branch (3 – 35 keV) giving access to analyses over a large energy range. It is equipped with calibrated photodiodes to acquire the reflected (or transmitted) X-ray beam and a silicon drift detector (SDD) to record the fluorescence spectra. The photodiodes were accurately calibrated using an electrical substitution cryogenic radiometer and the SDD was calibrated using the SOLEX lab-source. CASTOR is also equipped with a heating module, allowing to perform combined analysis of thin films under a range of temperatures up to 300°C. The fluorescence spectra recorded at grazing angles during a GIXRF experiment are analyzed with the PyMCA or COLEGRAM [2] softwares. The experimental data of both the XRR and GIXRF acquistions are analyzed simultaneously with a Mathematica® program in order to derive the parameters of interest such as the layer thicknesses, roughness, composition, density. We will give examples of recent combined analysis performed on some new materials. [1] Y. Ménesguen, B. Boyer, H. Rotella, J. Lubeck, J.Weser, B. Beckhoff, D. Grötzsch, B. Kanngießer, A. Novikova, E. Nolot and M.-C. Lépy, X-Ray Spectrometry, 46, 303-308 (2017). [2] H. Ruellan, M.-C. Lépy, M. Etcheverry, J. Plagnard, J. Morel, Nuclear Instruments and Methods in Physics Research Section A, Volume 369, 651-656 (1996)

Resume : Cu-doped Y-stabilized ZrO2 (Cu-YSZ) nanopowders calcined at T=800-1100°C were studied by electron paramagnetic resonance (EPR), photoluminescence (PL), diffused reflectance and transmission electron microscopy (TEM) methods. It was found that X- and Q-bands EPR spectra contain broad signal and a set of narrow lines caused by Cu doping. When calcination temperature rises, the broad line contribution decreases, while that of narrow lines increases. Diffuse reflectance and TEM studies showed Cu segregation to the grain surface being accompanied by tetragonal-to-monoclinic phase transformation and appearance of specific green-yellow PL emission. This PL was the most intense in the powders calcined at T=1000°C. The concentration of EPR centres responsible for narrow lines was found to be 1020 centres/g for these powders. Simulations of EPR spectra allowed determining for the first time the parameters of narrow lines as follows: S=1/2, I=3/2, gx=2.021, gy=2.026, gz=2.168, Axx~40*10-4 cm-4, Ayy~35*10-4 cm-4, Azz~186*10-4 cm-4, Axz~10*10-4 cm-4, Ayz~5*10-4 cm-4 for the 63Cu isotope. The analysis of EPR data shows that this centre corresponds to CuZr2+ ions situated in monoclinic ZrO2 lattice. The comparison of EPR, PL and PL excitation spectra leads to the conclusion that this centre participates in green-yellow PL emission that is excited through light absorption by oxygen vacancies.

Resume : The Wollaston probe used in the last decades in AFM for high resolution thermal conductivity measurement of thin films is not commercialized anymore but the idea behind it can still be exploited for building non-AFM probes. In this work one present preliminary results regarding a new experimental method based on a 50 microns diameter, hand fabricated, hot-probe of Pt90/10Rh alloy which is used to measure the Seebeck coefficient of thin films deposited on glass substrates. Compared with classical methods for measuring Seebeck coefficient based on heater-heat sink ensemble deposited on film surface instrumented with thermocouples, heated metallic rods with built-in thermocouples or microfabricated structures the proposed method provides simplicity in implementation, 50-100 microns spatial resolution, it eliminates the need of large area samples, is fast, reliable and low cost. A thermal model for heat transfer in the probe and to the sample is developed in order to find out the temperature distribution in the probe. The model showed that the ratio of the probe temperature rise in the contact point and average temperature rise is basically independent on electrical current through the probe and film thermal properties. This issue can be used to measure the Seebeck coefficient of the sample within 10% precision. Moreover, the contact radius and thermal contact resistance does not necessary to be known but only the pairs which are fitting the probe thermal resistance in contact with the film-substrate ensemble. This is a great simplification compared with the AFM based hot probe methods which determines these two parameters priori by calibration of two substrates with known thermal conductivity. The method is validated by measuring using the proposed method the Seebeck coefficient on three reference samples with known thermoelectric power. After validation, the method is intended to be used to measure the Seebeck coefficient of nanocrystalline BixSb2-x Te3, x=0, 0.15, 0.25, 0.35, 0.45, 0.55 thin films, of 85nm thickness, deposited by CVD on glass. The results will be compared with data from literature in order to assess their performance for thermoelectric applications.

Resume : With the aim of finding an interpretation for the isomerization reaction of icosadeca-ene by quantum methods, we have studied a series of three molecules giving the following results:  The studied segments (C20H20, C20H10F10, C20H10Cl8, C20H10Br8 and C20H10I8) are very stable. This stability is justified by the HOMO-LUMO found energy gap. However, examination of the stability of several conformations shows that the trans conformer is more stable than the cis conformer in the general assembly.  According to the study of different reaction profiles, we noticed that the size and nature of the dopant plays a very important role on the evolution of the activation energy.  From the obtained values of the activation energy, we find that the speed constants of the isomerization reaction are in the order: kC20H22 >> k C20H10F10 >> k C20H10Cl10 >> k C20H10Br10 >> k C20H10I10  The search for intermediate products during the transition Cis-Trans shows that the geometric parameters (angles and dihedral angles) are the most varied settings, this remark has been observed in the case of substituted and non-substituted icosadeca-ene.  The methods of calculations performed in this work are the Ab-initio and DFT methods, with the bases (6-31G, 3-21G **). All these calculations are performed with the Hyperchem software, where parameters obtained are in a closer order to those obtained with the Gaussian 03W software  Examination of different molecules obtained during the Cis-Trans isomerization reaction shows that the total energy of the resulting intermediate product is of the order of -10487.05 eV, corresponding to a 0.87eV activation energy (23.67 kcal / mol).  With the same HF method (6-31G and 3-21 G**), a close geometry was obtained for the intermediate product in the isomerization reaction with a total energy of 0.93 eV (25.30 kcal/mole), which shows that the different values of the activation energy obtained by the HF and DFT methods at the 6-31G level can be compared to those obtained by Ito, Montaner and Bernier. Keywords: Ab-initio; DFT; kinetics; isomerisation; substituted icosadeca-ene

Resume : To address the challenges associated with energy generation, storage and transfer in the 21st century, innovations in the field of advanced thin film materials need to be transferred as directly as possible into the production process to ensure a fast lane of technological developments. Complex thin films have to be accurately manufactured with respect to their spatial and elemental composition, interface properties and thicknesses. The reliable analyses of these properties is important in the development and production of advanced thin films. Synchrotron radiation-based X-ray spectrometric methods as Grazing Incidence X-Ray Fluorescence (GIXRF) and Near-Edge X-ray Absorption Spectroscopy (NEXAFS) allow for the variation of the analytical sensitivity, and selectivity needed to effectively reveal the spatial, elemental, and chemical specimen parameters of layers down to the nanometre range. By using radiometrically calibrated instrumentation and knowledge on atomic fundamental parameters a reliable and non-destructive characterization of layer stacks with respect to their mass deposition is possible without using any calibration sample or reference materials. For this purpose, the PTB operates fully characterized X-ray beamlines at the electron storage ring for synchrotron radiation at BESSY II in Berlin. In this work, differently tempered nano layers of AlOx prepared by atomic layer deposition and different mixtures of TiN and WN were characterized.

Resume : In this study, we used quantum chemistry calculations in order to determine some kinetic parameters of the isomerization reaction of the substituted icosadeca-ene. The studied molecules are: (C20H20, C20H10F10, C20H10Cl8, C20H10Br8 and C20H10I8) Cis and Trans. One of the adopted ways to access these parameters (activation energy, rate constant, etc ...) is looking for the transition state that is based on the exploration of intermediaries during the passage of Cis-Trans isomerization process. The study of a ten molecules series gives the following results: * The trans conformer is more stable than the Cis. * The activation energy changes very greatly depending on the size and nature of the substituent according to the reaction profile. * The constants of the isomerization reaction rates are in the following order: kC20H22 >> k C20H10F10 >> k C20H10Cl10 >>k C20H10Br10 >> k C20H10I10. * The geometrical parameters vary considerably according to intermediate products The calculation methods are DFT (TD-B3LYP) and Ab-initio methods at STO-3G*. Keywords: substituted icosadeca-ene, kinetics; isomerisation, HF (AM1+PM6), DFT

Resume : The remarkable properties of metallic nanoparticles supported on a substrate reside in their individual nanoscale features as well as in their collective behaviour as an assembly. Therefore, the control of their overall design is of great interest. In this work, we present the fabrication process and the characterization tools of stabilized cobalt nanoparticles (Co NPs) produced by plasma assisted solid state dewetting of sub 3 nm cobalt films deposited on TiSiN supports. Such process reveals to be a promising and non-expensive approach as compared with patterning. The model of dewetting process is analysed from kinetic and thermodynamic points of views. Vibrating sample magnetometry (VSM) and Brillouin light scattering (BLS) techniques were used to investigate both static and dynamic magnetic properties of Co NPs. Ordered arrays of Co NPs with densities up to (4.10^11 NP/cm2) were synthesized. Their shape, size and density were tuned mainly by dewetting parameters and initial Co film thickness. VSM measurements showed relatively high coercivity values depending on Co NPs arrays design, and have been discussed within the frame of magnetic anisotropy introduced by a small deviation to sphericity of the NPs. BLS measurements revealed an unusual reversed Stokes/anti-Stokes height asymmetry, introduced by nanostructuring in comparison to the native layer, revealing that such assembly of NPs behaves as an effective magneto-optical material with tunable properties.

Resume : The results obtained through the optimization of molecules gave us the different distances and angles according to the methods and bases applied with a C2v symmetry. We were able to determine the total energies, the energy gap ΔE (HOMO-LUMO) of the four conformers trans-transoid; trans-cisoid; cis-transoid; cis-cisoid. (the semi empirical AM1+PM6 at 6-31G and 3-21G** levels) and finally a comprehensive analysis on the topological charges. The analysis of the results show that for the eight molecules, the trans-transoid conformer is energetically very stable compared to the cis-cisoid one, this stability is confirmed by the obtained values for the total energy. The increase in the stability energy leads to a less important Homo-Lumo energy gap. The analysis of the optimized geometrical parameters of the twelve molecules using the AM1 and PM6 methods, are in agreement with the experimental structures characterized by X-ray diffraction. Finally, we were able to determine the reaction profiles of the Cis-Trans isomerization reactions of the hexadecaocta-ene in the gas phase, and to calculate the activation energy (Ea), as well as the diagrams of energies E (eV) based on the coordinates of the isomerization reaction of its molecules, and molar absorption according to energy calculated by the method HF at 6-31G and 3-21G** levels. Thus we have to determine the Spectrum IR of all the molecules by (AM1) and PM6. Keywords: substituted hexadecaocta-ene, semi empirical, HF (AM1+PM6),

Resume : Hybrid organic-inorganic perovskites are a promising material for thin-film solar cells, combining the advantages of high charge-carrier mobility and strong optical absorption to achieve remarkable efficiencies together with the low-temperature and low-cost processability. However, their practical utility remains uncertain due to the notoriously short operation lifetime. Efforts to overcome this challenge are frustrated by the complexity of the degradation mechanisms and the difficulty of obtaining reproducible results. There is an outstanding need for reliable techniques to probe the degradation mechanisms through detailed nano-scale characterisation of chemical changes and their impact on optoelectronic properties. In this study, a well-defined wedge cross section through a complete perovskite device stack was prepared by a secondary ion sputtering. The wedge was imaged with the 3D OrbiSIMS instrument to resolve the chemistry of the layers in the device, then the devices were transferred under vacuum (to prevent contamination of the freshly exposed surfaces) into a glovebox for correlative imaging by Atomic Force Microscopy (AFM) and Photoluminescence (PL) imaging. This approach offers combined chemical and optoelectronic measurements of the different components in a working perovskite solar cell. Comparison between a pristine and degraded devices reveal the interdiffusion of layers and chemical changes related to the degradation of nanoscale optoelectronic performance.

Resume : Liquid-metal jet X-ray sources promise to deliver high photon fluxes, which are unprecedented for laboratory based X-ray sources, because the regenerating liquid-metal anode is less sensitive to damage caused by an increased electron beam power density. For some quantitative X-ray analysis techniques, knowledge of the absolute photon flux is needed. However, a precise experimental determination of the photon flux of high-performance X-ray sources is challenging, because a direct measurement results in significant dead time losses in the detector or could even harm the detector. Indirect determinations rely on data base values of attenuation or scattering cross sections leading to large uncertainties. In this study we present an experimental determination of the photon flux of a liquid-metal jet X-ray source by means of elastic and inelastic photon scattering. Our approach allows for referencing the unpolarised output radiation of the liquid-metal jet X-ray source to polarized synchrotron radiation in a simple setup. Absolute photon fluxes per solid angle are presented with a detailed uncertainty budget for the characteristic emission lines of Ga Ka and In Ka for two different acceleration voltages of the X-ray source. (DOI: 10.1039/c9ja00127a)

Resume : The effect of plasmon-phonon interaction is investigated for ZnO films grown on p-type Si substrates by radio frequency magnetron sputtering. ZnO target was sputtered in pure argon or mixed argon-oxygen plasma. The film properties were investigated using atomic force microscopy, spectroscopic ellipsometry and specular Fourier-transformed infrared reflection followed by the dispersion analysis of theoretical and experimental values for the reflection coefficient. The results indicate that the films grown in argon plasma had larger surface roughness that increases with deposition time. Contrary to this, the films produced in argon-oxygen plasma were found to be denser and smoother. They demonstrate also an abrupt absorption band-gap edge that was explained by the lower number of native defects (such as Zn interstitials) contributed to the film conductivity. Analysis of specular infrared reflection spectra revealed the influence of plasmon of the substrate on the plasmon-phonon interaction in ZnO film. The films grown in pure argon plasma demonstrated higher concentration of free carriers and smaller their mobility in comparison with corresponding parameters of the films grown in argon-oxygen mixed plasma. The findings of this work demonstrate an application of this approach for the prediction of the properties of textured thin films.

Resume : Total Reflection X-ray Fluorescence (TXRF) offers some appealing micro-analytical properties for the biomedical and biochemical communities, in constant need of sensitive screening and quantification methods for characterizing the effect and/or fate of novel nanomaterials or drugs designed to be used in the clinics. By its nature surface sensitive, allowing a simultaneous determination of the elemental compositions with detection limits in the low picogram range, TXRF is presenting an interesting alternative to primary methods such as Inductively coupled plasma (ICP) based techniques, which rely on tedious sample preparation procedures and potentially suffer from low recovery rates. Used thoroughly, TXRF analysis may help in 1) classifying samples, their origins or interdependencies by recognition of the elemental information, 2) providing a quantitative analysis of the elements even in complex matrices, 3) predicting the properties or effects of the elemental occurrence in a system via quantitative structure-activity-function relationships, or even 4) monitoring processes and status by the development or knowledge of a sensor e.g. elemental occurrence or threshold. TXRF analytical potential will be illustrated in pharmaceutics, by assessing elemental impurities in Active Pharmaceutical Ingredients (API) and carriers, and in nanomedicine, by quantifying nanoparticles cellular delivery and uptake, and probing bio-labelled molecules and their substrates for bio-platforms.

Resume : Understanding the active state of electrocatalysts in operando conditions is essential for improved understanding of mechanism and rational design of efficient and stable systems. Environmental transmission electron microscopy (ETEM) can contribute to this topic since it offers a comprehensive study of interactions of catalyst surfaces in controlled environment of water, in different reactive and non-reactive gases1, in electric potentials2 and at atomic column resolution. Here, we study the atomic dynamics of mobile manganese (Mn) adatoms at single crystalline edges of La1-xSrxMnO3 (x=0.4) (LSMO) manganites in high vacuum (HV), reactive environment (H2O, O2) and in inert atmosphere (N2). LSMO shows reversible Mn adatom mobility on top of stable A-site cations. To study atomic dynamics in ETEM, the preparation of ultrathin electron transparent TEM lamella with minimum preparation induced defects and avoiding any catalytically relevant impurities is required. Considerably modifying the widely used FIB lift-out technique by using a photoresist protection layer and attaching the TEM lamella to Cu grid by using Cu redeposition technique results in Pt-free high quality samples. Loss of oxygen due to ion milling can be compensated by an electron beam induced oxidation in O2 environment in the ETEM, leading to a well-defined highly crystalline surface structure3. The structure of LSMO (001) surface was then studied in different ambient with atomic column resolution with aberration corrected high-resolution TEM. Remarkably, columns of moving Mn adatoms have been identified on top of stable La/SrO terminated surfaces. It is observed that the Mn adatom hopping on the (001) surface of LSMO in a thin liquid H2O layer is 20 times higher than in high vacuum or gases, such as O2 and N2. At step edges, a strong reduction of the Mn adatom hopping rate in H2O from >4s-1 to r <1.4 s-1 is observed due to the presence of an Erich Schwoebel barrier. Our studies shed light on the role of Mn adatoms on manganite perovskite interfaces to H2O for the oxygen evolution catalysis in electrochemical water oxidation. It implies that partial solvation of active Mn surface adatoms might be essential for the understanding of the active state of Mn-O based catalyst and opens new perspectives in atomic scale design of efficient and stable electrode surfaces for OER. References 1. Ch. Jooss S. Mildner, M. Beleggia, D. Mierwaldt, V. Roddatis in “Controlled Atmosphere Transmission Electron Microscopy - Principles and Practice”, edited by Jakob Birkedal Wagner and Thomas Willum Hansen, Springer 2016 2. S. Mildner, M. Beleggia, D. Mierwaldt, Th. W. Hansen, J. B. Wagner, S. Yazdi, T. Kasama, J. Ciston, Y. Zhu, and Ch. Jooss, Environmental TEM Study of Electron Beam Induced Electrochemistry of Pr0.64Ca0.36MnO3 Catalysts for Oxygen Evolution J. Phys. Chem. C, 119 (2015) 5301–5310. 3. V Roddatis, G Lole and Ch Jooss, In situ preparation of Pr1-xCaxMnO3 and La1-xSrxMnO3 catalyst surface for high resolution environmental transmission electron microscopy. Catalysts (2019). doi:10.3390/catal9090751

Resume : The impact of isovalent dopants on optical and structural properties of HfO2 matrix attracts significant attention due to the unique optical and electrical properties of such materials. In the present work, the effect of annealing temperature on the properties of Ge-doped HfO2 thin films is investigated by spectroscopic ellipsometry, Raman scattering, XRD and TEM methods. The films were grown by radio-frequency top-down magnetron co-sputtering of pure Ge and HfO2 space-apart targets. The Ge content in the films was varied in the range 0-60 at % via power density applied on Ge target. Besides, pure Ge and pure HfO2 films were prepared for comparison. The samples were annealed in at T=300–1000 °C for 30 s in a nitrogen atmosphere. As-deposited homogeneous Ge-HfO2 films were found to be amorphous contrary to pure HfO2 films. This fact confirms that Ge incorporation stabilizes the amorphous HfO2 phase that was found to be stable up to T=600 °C. The T increase up to 800°C results in the formation of pure Ge nanocrystallites as well as tetragonal HfO2 grains. Further T rise favors considerable Ge out-diffusion from the films followed by the appearance of the monoclinic HfO2 phase. At the same time, no Si presence was revealed in the film volume testifying on the stability of these films in direct contact with Si substrate. The mechanism of the film phase transformation is discussed.

Resume : Electronic Devices Industry is known to have been driven since its early stages by a continuous technological effort of miniaturization because of the dual need of manufacturing cost reduction through integration and offer to the user market of smaller and smaller electronic applications, more efficient, versatile and differentiable. Silicon wafer manufacturers have been forced to provide larger size silicon wafers, 300mm diameter is nowadays covering more than 50% of the total market, with dimension and density of residual defects moving from microns to nanometers, from ppt to ppq or even less. In this context, proper choice of measurement technique and set up which can guarantee measurement reliability to detect a given defect and provide information of its distribution inside the wafer is mandatory. It has to cope the need to control material quality in a range more frequently close to the measurement detection limit and the need to improve the associated manufacturing process capabilities. The paper intends to propose a few examples in the area of crystallographic/morphological defects and chemical impurities on silicon wafers, reviewing the defect analysis approach inside a manufacturing environment. Discussion will also involve the final product certification data reporting which tends to convey in a very synthetic format the whole measurement and control process.

Resume : The Rutherford backscattering spectroscopy (RBS) is the best method of host element depth concentration profile determination in thin films and material surface layers. For the elements contamination analysis it can be added by the Particle Induced X-ray Emission (PIXE) and Total X-ray Reflection Analysis (TXRF) experimental methods. TXRF measurements are more effective for trace analysis of elements characterized by high energy of characteristic radiation yield and present data about element composition of surface layer with thickness 3-5 nm with high sensitivity. The X-ray planar waveguide-resonator (PXWR) including into the TXRF spectrometer setup allows to decrease the contamination detection limits on 3 orders. PIXE method is very perspective for light element analysis but it allows to obtain volume contamination concentration data. PXWR including into the PIXE measurements setup allows to receive new high effective experimental method for surface layer element diagnostics: TXRF-PIXE. Complex application of methods allows to get total picture about object element composition without it destruction. Suitable experimental data are discussed.

Resume : Today Li-ion batteries are the main power source of choice for full and hybrid electric vehicles and portable electronics devices.1,2 However, the use of Li the main global power source for electromobility and grid application is questionable due to limited lithium resources.3 Alternatives to lithium, such as Na, K, Ca, Mg and Al, have attracted great interest in the last years due to the greater abundance of these elements. Among them Al is one of the most abundant metal elements in the Earth's crust and is characterized by an extremely high volumetric capacity of 8040 mA h cm-3, which is four times higher than that of lithium, making it an extreme good candidate to replace Li.3 In this work we propose an operando characterization in terms of X-Ray Diffraction (XRD) combined with X-ray tomography of two full-battery systems based on pyrolytic graphite (PG) and natural graphite (NG) as anodes. Those systems are very similar but show different electrochemical behaviors in terms of reversibility and capacity retention after the first cycle. 1. K. E. Aifantis and S. A. Hackney, in High Energy Density Lithium Batteries, ed. K. E. Aifantis, S. A. Hackney and R. V. Kumar, WILEY-VCH Verlag, Weinheim, 2010, pp. 81–101. 2. D. A. Notter, M. Gauch, R. Widmer, P. Wäger, A. Stamp, R. Zah and H.-J. Althaus, Environ. Sci. Technol., 2010, 44, 6550–6556. 3. G. A. Elia, K. Marquardt, K. Hoeppner, S. Fantini, R. Lin,E. Knipping, W. Peters, J.-F. Drillet, S. Passerini and R. Hahn, Adv. Mater., 2016, 28, 7564–7579.

Resume : Atmospheric oxygen that we live on is the result of a fundamental evolutionary step in photo-synthesis which occurred on Earth 2-3 billion years ago [Biello 2009]. The water oxidation in natural photosystem II accounts for 50% of this oxygen. The man-made analog to this natural process is water oxidation in photoelectrochemical cells - one of the most complex processes in physical chemistry. I will showcase how modern x-ray spectroscopy methods have assisted in the understanding of the molecular processes which occur in natural [Bora 2013, Ralston 2000, Visser 2001] and in man-made "photosystems". A most recent example is the element and orbital specific identification of transient electron holes in iron oxide [Braun 2012], chemical surface intermediates [Bora 2011] and changes in the water molecules in the electrochemical double layer during photoelectrochemical water oxidation [Braun 2016]. I will also demonstrate how the electronic structure evolution is quantitatively paralleled by the electric transport properties of the electrodes during operation. [Biello 2009] The Origin of Oxygen in Earth's Atmosphere. In Scientific American 2009. [Bora 2011] J Phys Chem C 2011, 115:5619-5625. [Bora 2013] J ELECTRON SPECT RELATED PHEN. 2013, 190:93-105. [Braun 2012] J Phys Chem C 2012, 116:16870-16875. [Braun 2016] Catalysis Today 2016, 260:72-81. [Ralston 2000] JACS 2000, 122:10553-10560 [Visser 2001] Journal of the American Chemical Society 2001, 123:7031-7039

Resume : We have developed in-fab monitoring strategy for microporous silicon films fabricated by etching 200 mm p-doped (100) silicon wafers in HF-based solutions. We have generated different porous silicon films with porosity in the 50 to 60% range and thickness from 6 to 20 µm. First, high-resolution X-ray diffraction (HR-XRD) permits to quantify the strain inside the porous silicon layer and to assess the influence of the resistivity of the substrate on the uniformity of the crystalline properties at the wafer level. Secondly, spectroscopic ellipsometry (SE) and M-line spectroscopy permit to derive the optical properties of the films in the visible and near-infrared spectral range, and to reveal their variability, amid the wafer set and at the wafer level. We used these optical properties to model the Spectroscopic Reflectometry (SR) and the Fourier Transform Infrared spectroscopy (FTIR) data, in order to provide non-destructive mapping of the film thickness, with spatial resolution from 1 mm (FTIR) down to 20 µm (SR). The comparison with thickness maps obtained by Scanning Electron Microscopy (SEM) demonstrated a 2% (resp. 5%) match between SEM and FTIR (resp. SR) deduced thicknesses. At the end, the combination of HR-XRD and optical analysis, i.e FTIR and SR strategy based on SE and M-line spectroscopy, fits the requirement for fast operator-compatible monitoring of the uniformity of the porous silicon process at the wafer level.

Resume : Cuprous oxide (Cu2O) is a promising material for emerging electronics. Bandgap and defect states estimation of Cu2O film grown by chemical vapor deposition (CVD) technique on SiO2/Si substrate at 600°C was performed in this work using various spectroscopies. XRD and XPS confirmed the phase purity of deposited film. The optical bandgap of Cu2O was 2.35 eV which was calculated from absorption spectroscopy (UV-Vis). Using ultraviolet photoelectron spectroscopy (UPS) and absorption spectroscopy (UV-Vis), the nature of deposited Cu2O was confirmed as a p-type semiconductor. Using UPS, the energy level of the valence band and Fermi level of the intrinsically p-doped Cu2O film were determined as 6.02 eV and 5.62 eV respectively from the vacuum level. The temperature dependence photoluminescence spectra of these films exhibited emission peaks at ~1.4 eV and ~1.72 eV which corresponds to energy states of copper and oxygen vacancies level in the bandgap. Photoluminescence spectra also show a peak at ~2 eV which is due to the relaxation of free excitons to the valance band.

Resume : Up to date, most of the size of the van der Waals (vdW) materials and their heterostructures are in the range of several tens of micro-meter square, and because of the monolayer nature, the thicknesses of these systems are mostly within the nano-meter range. With the characteristics of the dimensionality, it is impossible to study the properties of the vdW systems without the help of microscope. Here, we present a synchrotron-radiation based soft X-ray photoelectron microscopy, which utilizing a Fresnel zone plate optics to focus the monochromatic soft X-ray down to 100 nm spot size. By combing the fine spot size and the surface sensitive nature of photoelectron spectroscopy, this system is an ideal platform to study the intrinsic properties of vdW systems. Some of the recent studies regarding the electronic and chemical properties of vdW systems will be presented and discussed.

Resume : The success of graphene opened a door for a new class of chalcogenide materials with unique properties that can be applied in several applications such as the semiconductor technology [1], optoelectronics [2], hydrogen evolution [3], photodegradation of organic dyes [4] or electrodes in Li ion batteries [5]. TMDCs can be prepared by various top-down (e.g. exfoliation) and bottom-up techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) growth techniques [1]. MoS2, a typical representative of TMDCs, has been widely studied for several applications. Recently, the possibility to employ ALD as a technique to grow MoS2 has been reported. In these works (CH3)2S2 [6] or H2S [7, 8] were used as the S precursor and Mo(CO)6 [6], MoCl5 [7] or Mo(thd)3 [8] as the Mo precursors. Another interesting TMDC is MoSe2 since it possesses a higher electrical conductivity than MoS2 [9, 10]. Recently, we have shown that ALD deposition of MoSe2 [11] or Mo-O-Se [12] using ((CH3)3Si)2Se as the Se precursor and the MoCl5 or Mo(CO)6, respectively, as the Mo precursors is feasible. Since the applications of the aforementioned 2D materials involve chemical and/or electronic processes on the surface, the XPS characterization is a crucial tool to evaluate their quality in terms of the composition. Therefore, this work will focus on the changes of surface chemical state of synthesized MoS2 and MoSe2 by ALD over different substrates (Silicon, Quartz, Titanium and TiO2 nanotubes). Recent results will be presented and discussed. References: [1] A. V. Kolobov, J. Tominaga, Two-Dimensional Transition-Metal, Dichalcogenides. Springer Series in Materials Science, Springer International Publishing AG, Switzerland 2016 [2] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, A. Kis, Nat. Nanotechnol. 2011, 6, 147. [3] L. Wang, Z. Sofer, J. Luxa, M. Pumera, Adv. Mater. Interfaces 2015, 2, 1500041 [4] Y. Wu, M. Xu, X. Chen, S. Yang, H. Wu, J. Pan, X. Xiong, Nanoscale 2016, 8, 440 [5] D. Ilic, K. Wiesener, W. Schneider, H. Oppermann, G. Krabbes, J.Power Sources 1985, 14, 223 [6] Z. Jin, S.Shin,D.H.Kwon, S. J.Han,Y. S.Min,Nanoscale 2014, 6, 14453. [7] L. K. Tan, B. Liu, J. H. Teng, S. Guo, H. Y. Low, K. P. Loh, Nanoscale 2014, 6, 10584 [8] M. Mattinen et al., Adv. Mater. Interfaces 2017, 4, 1700123. [9] D. Kong, H. Wang, J. J. Cha, M. Pasta, K. J. Koski, J. Yao, Y. Cui, Nano Lett. 2013, 13, 1341. [10] A. Eftekhari, Appl. Mater. Today 2017, 8. [11] M. Krbal et al., Phys. Stat. Sol. RRL, 2018, 12, 1800023 [12] S. Ng et al., Adv. Mater. Interfaces 2017, 1701146.

Resume : Mesoporous silica films are typically produced by evaporation-induced self assembly (EISA), but vertical alignment of the pores to the substrate is very difficult to achieve. Hexagonal arrays of vertically aligned mesopores can be achieved by electrochemically assisted surfactant assembly (EASA). Under the Advanced Devices by Electroplating EPSRC programme grant (EP/N035437/1) we are working on the integration of nanowire semiconductor structures into electronics, using aligned mesoporous templates as host for the electrodeposition of high quality chalcogenide semiconductors. The self-assembly of a cationic surfactant (typically cetyltrimethylammonium bromide) close to the substrate surface relies on the application of a negative potential to an electronically conductive substrate, but also leads to the formation of spheroidal surface aggregates, limiting the obtainable film thickness to a few hundreds of nm. Grazing incidence small angle X-ray scattering (GISAXS) allows for the non-destructive structural analysis of thin films with high statistical relevance in lateral and vertical direction. In this work, we show the results obtained from in situ GISAXS experiments done during the EASA of silica, following the evolution of the structure formation in real time with sub-second time resolution. From this, suggestions to a more detailed mechanism of formation are made through detailed data analysis.

Resume : Surface X-ray diffraction (SXRD) studies are important to determine the 3D structure of single crystal surfaces and surface structures that form in the presence of reactive gases. [1,2] Due to the weak interaction between X-rays and matter, the surface-related diffraction signal is much lower than that of the bulk. Synchrotron radiation is thus used in conventional SXRD studies to get the desired signal to noise ratio. Herein we try to bring this technique from the synchrotron to the lab which makes it possible to prepare beamtimes more efficiently. A SXRD setup was installed at Lund University by Sirius XRS. It is equipped with a Mo microfocus X-ray source (17.6 keV) and a 2D noise-free, hybrid photon counting detector. A specially designed reaction chamber was mounted which allows us to prepare samples by standard surface science techniques and to do catalytic tests at pressures up to 1 atm. By using a sealed tube microfocus X-ray source instead of synchrotron radiation, experiments require longer exposure times and adequate shielding of X-ray photons from diffuse scattering is necessary. After the optimization of these parameters, it was possible to study CO oxidation on different oxides formed on Pt(110) and to successfully determine the active phase. [1] U. Hejral, et al., Phys Rev. B., 96, 2017, 195433. [2] J. Gustafson, et al., Science, 343, 2014, 758.

Resume : Rembrandt van Rijn (1606-1669) is renowned for his innovations in painting materials and techniques, like his impasto process which consists in laying thick white paint protrusions to enhance light reflection. Like most artists of his time, Rembrandt used lead white pigments, that is, mixtures of cerussite PbCO3 (C) and hydrocerussite Pb3(CO3)2(OH)2 (HC) obtained by lead corrosion. Microsamples collected in the impastos of six Rembrandt’s masterpieces of Dutch and French museums were analyzed by synchrotron diffraction on ESRF beamlines ID13 (μ-XRD mapping) and ID22 (hi-res XRD) to determine the composition and microstructure of the pigments by Rietveld analysis and infer the preparation processes. The most striking feature is the systematic presence of plumbonacrite Pb5(CO3)3O(OH)2 (PN), a rare mineral, never observed heretofore in ancient paintings, only stable in highly alkaline media and indistinguishable from HC by spectroscopic methods. Rembrandt’s PN, 20-40 w% of the pigment, consists in nanoplatelets about 10 nm thick. XRD mapping reveals PN aggregates that account for a neofomation process in the paint. In line with the XRD measurements and lab-made mock-ups, the most probable explanation is the use by the Master of high amounts of lead oxide as a siccative for the impasto oil. Indeed, basic PbO in excess is highly reactive towards acid C, yielding PN, as confirmed by the unusual low C ratio associated. V. Gonzalez et al., Angew. Chem. Int. Ed. 58 (2019) 5619-5622.

Resume : Spherical silica nanoparticles are developed to be used as reference material for monomodal and bimodal dispersion. The manufacturing quality of these materials is essential and often is not perfectly controlled. Improving this fabrication requires a fine understanding of synthesis, coupled with the expertise of in-situ or ex-situ analysis methods. This constitutes a new challenge for the analysis: it is indeed a question of determining not only average characteristics (Size, chemical composition, and shape...) but also the concentration and the distribution over the population studied. Small-Angle X-ray Scattering allows very precise measurements that can be directly linked to the metric system (metrological traceability). We developed a laboratory instrument dedicated to the in-situ characterization of nanoparticles during the synthesis, which enables fast measurements and the monitoring of the parameters. Measurement protocols and software processing chains (i.e. size distribution) are also combined & optimized.

Resume : Metal halide perovskite (MHP) materials exhibit exceptional performance characteristics for low-cost optoelectronic applications. Though widely considered defect tolerant materials, perovskites still exhibit a sizeable density of deep sub-gap non-radiative trap states, which create local variations in photoluminescence [doi: 10.1126/science.aaa5333] that fundamentally limit device performance. These trap states have also been associated with light-induced halide segregation in mixed halide perovskite compositions [doi: 10.1021/acsenergylett.8b02002] and local strain [doi:10.1039/C8EE02751J], both of which can detrimentally impact device stability. The origin and distribution of these trap states remains unknown as multiple, complimentary multi-modal techniques are required to probe their location and surrounding structure and composition and MHPs damage rapidly under the electron beam. Understanding the nature of these traps will be critical to ultimately eliminate losses and yield devices operating at their theoretical performance limits with optimal stability. In this talk, we outline a low dose, multi – technique framework to reveal the structural origins of non-radiative recombination sites in (Cs0.05FA0.78MA0.17)Pb(I0.83Br0.17)3 thin films[Accepted, Nature]. By combining scanning electron diffraction and energy dispersive X-ray spectroscopy, with photoemission electron microscopy (PEEM) measurements we reveal that nanoscale trap clusters are distributed non-homogenously across the surface of high performing perovskite films and that there are distinct structural and compositional fingerprints associated with the generation of these detrimental sites.

Resume : Solar power has a major role in the crucial transition to low carbon power. Perovskite solar cells, in particular, are a great photovoltaic alternative as they exhibit excellent energy harvesting abilities and do not require energy-intensive manufacturing techniques. While poor stability during scale-up of perovskite photovoltaics limits their widespread commercial use, the key is the relationship between the microstructure and properties. Thus, an analytical strategy is necessary for resolving the microstructure at the nanoscale to efficiently tune the perovskite properties beyond the current state of the art. We have developed a magnetic sector Secondary Ion Mass Spectrometer (SIMS) and coupled it to a Helium Ion Microscope (HIM). Owing to this, we combine the best of both worlds; the high lateral resolution in secondary electron imaging of the HIM with the high detection limit of our internally developed SIMS instrument. In SIMS mode, we are able to detect elements in the full mass range with a lateral resolution below 15 nm. The SIMS data can be correlated with sub-nm resolution secondary electron images. We will show several analytical studies completed with HIM-SIMS, among them, a cross-sectional chemical map of a multi-cation based perovskite device where different thin films at the nanoscale can be distinguished. HIM-SIMS is a versatile and powerful technique for the improved understanding of the impact of microstructure on photovoltaic performance and stability.

Resume : Lateral inhomogeneities in material properties arise in Cu(In,Ga)Se2 solar cells from fabrication processes, growth conditions and its polycrystalline nature. An essential parameter defining the quality of the material is the carrier lifetime, which directly influences the open circuit voltage (Voc) and the performance of the devices. Time resolved photoluminescence (TRPL) is typically used to characterize the carrier lifetime. The low injection regime is the preferred measurement condition but is challenging to achieve experimentally, especially for mapping measurements, due to the difficulty to obtain a sufficient signal-to-noise-ratio. Achieving such conditions allows for a better understanding of the possible Voc limitations at standard test conditions due to lateral inhomogeneities. In this contribution, we evaluate a wide-field illumination microscopy technique to achieve low injection conditions. We will present the spatial distribution of carrier lifetime at both large and small scale (cm-μm) for different Cu(In,Ga)Se2 absorbers with different materials. The intensity and lifetime maps obtained revealed significant inhomogeneities with strong non-Gaussian distributions. An assessment of the impact of such distributions and its correlation to Voc and solar cell performance will be presented.

Resume : Photovoltaic devices using quinary (Ag,Cu)(In,Ga)Se2 (ACIGSe) alloy absorbers are reported to exhibit improved opto-electronic properties when using high-Ga concentrations which is due to a widened band gap compared to Cu(In,Ga)Se2 (CIGSe) [1]. The addition of Ag atoms allows reducing deposition temperatures, which is argued to decrease the intragrain defects in the chalcogenide structure. Alkali metals incorporated in the absorber, are widely-known to have a positive effect on the performance of the corresponding devices, possibly via suppression of recombination effects at interfaces. In CIGSe, alkali metals are commonly reported to segregate at grain boundaries and in ordered vacancy compounds [2]. The solubility of alkali metals is predicted to vary in ACIGSe, hence, investigations using high resolution characterization techniques are required to study the chemistry and microstructure relationships. ACIGSe absorber samples were deposited on soda lime glass (Na-rich) and high-strain point glass (K-rich), respectively, followed by KF-PDT. Transmission Kikuchi diffraction (TKD), glow discharge optical emission spectroscopy (GDOES), electron beam induced current (EBIC) and atom probe tomography (APT) were employed to analyze the structure, the local carrier concentration, as well as the local compositions in the absorber material. The composition in different grains and grain boundaries of the absorber were compared. Correlative microscopy provides here a deeper understanding of the opto-electronic behavior and microstructure. [1] M. Edoff, et al., IEEE J. Photovoltaics. 7 (2017) 1789–1794. [2] A. Stokes, et al., Sci. Rep. 7 (2017) 1–11.

Resume : Sequential infiltration synthesis (SIS) [1] consists of the cyclic exposure of a polymer to gaseous precursors used in atomic layer deposition (ALD), resulting in the growth of inorganic compounds. SIS is a promising technique for many applications, including the realization of complex inorganic nanostructures in block copolymers (BCPs) templates for microelectronics. In PS-b-PMMA BCPs systems, Al2O3 is grown by the reactions of trimethyl-aluminium (TMA) and H2O and infiltrates selectively in PMMA nanodomains due to their chemical affinity to TMA. The role of PS as a diffusion channel has been proposed to describe the mechanism of infiltration [2], however, the complete understanding of the process is still sought. In this study, we combine grazing-incidence X-ray fluorescence (GIXRF), transmission electron microscopy (TEM) and energy dispersive X-ray microanalysis (EDX) to provide insights into such a mechanism. Reference-free GIXRF analysis [3] was performed on a layer of PMMA resist for electron beam lithography (EBL), PS-r-PMMA and PS-b-PMMA layers infiltrated with Al2O3 in 1 to 10 cycles of ALD to obtain the absolute quantification of the aluminum content. GIXRF depth-dependent information on the distribution of target elements can be complemented with the imaging of the cross-sectional view of infiltrated polymer and chemical analysis provided by EDX. [1] Y. C. Tseng, et al., J. Mater. Chem, 21, 2011, 11722. [2] M. Biswas, et al., J. Phys. Chem. C, 119, 2015, 14585. [3] P. Hönicke, et al., Phys. Status Solidi A, 212 (3), 2015, 523.

Resume : Nano-characterisation techniques, including confocal microscopy, atomic force microscopy (AFM) and tip enhanced Raman scattering (TERS), rely on the ability of each instrument to resolve nano-scale features without distortions and artefacts, however, reference samples allowing to perform fully quantitative characterisation of their responses are not available. Calibration of lateral and depth resolution of advanced scanning-probe microscopy methods is currently very challenging and calls for the development of nanoscale standards with features in 10-200 nm range with various morphological and optoelectronic characteristics. We demonstrate the development of single-nanowire-based reference samples, where easily identifiable device positions each contain a semiconducting nanowire with a particular set of properties. Key parameters that are considered include: diameter and length, Raman response, photoluminescence and conductivity. The devices are self-assembled from a wide range of solution-processed semiconducting nanowires, including Si, Ge, InAs, InP, GaN, Ge/Si. Individual nanowires are positioned in pre-defined locations using electric-field assisted process, dielectrophoresis (DEP), by applying controllable DEP signal voltage and frequency. Nanowires are characterised, and various response metrics are analysed using conducting-AFM, confocal Raman, TERS and other techniques to establish which nanowire materials provide highly distinguishable responses, necessary for reference standards. Challenges in identifying most suitable nanowire materials, including their spectroscopic characteristics (e.g. Raman) and morphological features (e.g. diameters) are discussed and several reference samples for the characterisation of lateral and vertical resolution of nanoscale scanning probe techniques are suggested.

Resume : Mapping temperature distribution on an active microelectronic circuit is a way how to evaluate the circuit performance, locate the hot spots and better understand processes leading to potential device failure. Different methods are being used for these purposes, either contact or non-contact, having different spatial and temperature resolution and being based on different traceability chains. In this contribution we will concentrate on two of them, Scanning Thermal Microscopy and infrared microscopy. We will present key systematic errors in both types of measurements, best practices for making the measurement traceable and whole toolchain needed for interpreting the measured results. We will also discuss benefits and drawback compared to other high resolution thermal techniques, e.g. thermoreflectance measurements. The uncertainty sources will be estimated on basis of both measurments and numerical calculations. Quantitative results with examples of the full uncertainty budget will be demonstrated for measurements on commercially available integrated circuits.

Resume : Scanning microwave microscopy (SMM) is a still rather new member of the family of scanning probe techniques. It has attracted attention due to its ability to characterize various electrical properties of samples. The basic working principle is to send a microwave signal to the scanning tip, where it is reflected depending on the sample underneath. The material parameters at the tip-sample contact determine the measured reflection coefficient, S11, in amplitude and phase Here, we present our works to produce and characterize capacitive devices, which can be used as impedance standards to calibrate the SMM. The sample fabrication was done in a clean room to produce different gold micron-size structures supported by a free SiN membrane. After the fabrication, high resolution scanning electron microscope images were taken and analyzed. Then, analyzed images were imported into Comsol Multiphysics in order to estimate the capacitance of these devices. SMM measurements were conducted using our tuning-fork based SMM under ambient conditions with microwave frequencies between 1 and 50 GHz. Measured S11 signals show a clear contrast between regions with different impedance/capacitance. Last but yet importantly, we were able to demonstrate that the calibration method proposed by Hoffmann and others [1] can be applied to the SMM measurements our impedance standards. References: 1. J. Hoffmann, et al. (2018), A Calibration Algorithm for Nearfield Scanning Microwave Microscopes, IEEE-NANO, 2012.

Resume : Over the last decades the Focused Ion Beam (FIB) microscope became an indispensable tool for fundamental materials and applied research. Dual-beam systems comprise a FIB column where a focused beam of typically gallium ions originates from a liquid-metal ion source and a scanning electron microscope (SEM) column providing a focused beam of electrons. This arrangement enables precise structuring and high-resolution imaging at the same time. Equipped additionally with gas injection systems, hydrocarbon precursor gases can be inserted in the chamber allowing a local deposition of conducting (Pt, W, C) or insulating materials. One of the main advantages employing FIB instrumentation is that internal micro- and nanostructural sample features become accessible for site- and orientation-specific target preparation. However, the scope of applications of this technique goes beyond preparation of thin-foil samples for transmission electron microscopy. Here, the potential of FIB instrumentation for the fabrication of nanostructured devices from layered semiconductor material systems (PZT, AlGaN/GaN and AlN/GaN) for different analytical techniques such as Infrared Scanning Near-field Optical Microscopy, Scanning Microwave Microscopy and X-ray Spectrometry will be demonstrated.