ALTECH 2021 - Analytical techniques for precise characterization of nano materials

Resume : Obtaining detailed control of materials on the nanoscale is attractive in catalyst development, but lack of insight into the fundamental physical and chemical processes occurring on catalytically active surfaces often hampers the progress. Scanning Probe Microscopy techniques (SPMs) are strong techniques for gaining detailed insight, since they allow us to image the atomic structure of surfaces and sometimes directly see the result of catalytic reactions. I will show how we use the scanning tunneling microscope (STM) in interplay with photoemission spectroscopy techniques (XPS, NEXAFS) and reaction cells to investigate two important catalyst systems. We investigate the structure and catalytic properties of earth-abundant Co and Fe-doped Co oxide thin film grown on Au(111), which can be used for the oxygen-evolution reaction (OER) in electrochemical water splitting. Secondly, for the selective catalytic reduction reaction (SCR) for NOx pollution abatement, we explore the redox properties of well-defined VOx/anatase-TiO2 surfaces. For some of these studies, time-lapsed STM data are used to reveal the atomistic mechanisms involved in surface diffusion and reactions.

Resume : Hot Electron Nanonscopy and spectroscopy (HENs) is a recently developed technique relying on the unbiased emission of energetic electrons at a Schottky junction after plasmon decay, once excited by impinging laser excitation. Recently we employed this technique with an AFM-based architecture to exploit the nanometric spatial resolution and controlled interaction on several inorganic semiconductor and 2D materials, proofing an extremely high efficiency in hot carriers generation and high spatial resolution. Here we show the first application to p-doped organic semiconductor, broadening the range of applicability to a new class of materials where conductance is dominated by holes. At the same time, these studies pave the way to the possibility to study hot carriers conduction under controlled strain and deformation, and the influence of morphology on conductance. For this reason, we have coupled a Raman detection channel to the plasmon photonic decay channel at the tip, to provide structural information aside from the conductive/ spectroscopic one.

Resume : The study of dynamic processes in polymers and soft matter systems provides a deep insight into the different role of the molecular constituents into the final materials’ properties. Broadband dielectric spectroscopy (BDS) is among the best-established experimental techniques suitable for such studies. This technique allows probing the dipole reorientations and/or charge motions dislocations taking place inside the sample, when an external electrical AC-field is applied. However, BDS lacks spatial resolution, as many macroscopic techniques. To overcome this issue, we have developed during the past years AFM-based methods to perform local BDS measurements allowing for a lateral resolution < 100 nm. Our approach allows for direct access to the frequency-dependent dielectric permittivity of insulating thin films. Here, we present our recent advances in probing the molecular dynamics of polymer thin films by local dielectric spectroscopy. In particular, we investigated films of novel, bio-based polymer blends. Different thermal treatments allowed obtaining samples with distinct structures, as inferred from the surface features, as nanocrystals. We probed the molecular relaxations at different zones of the films. This approach allowed testing the potential miscibility of the components in these blends; a fact not directly evidenced by topographical and mechanical imaging alone, and which is of outmost important for possible applications of these materials.

Resume : The 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 SMM. The sample fabrication was done in 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 1-50 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 our SMM measurements. References: 1. J. Hoffmann, et al. (2018), A Calibration Algorithm for Nearfield Scanning Microwave Microscopes, IEEE-NANO, 2012.

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 high dielectric constant (high-k) materials based on Lead zirconate titanate (PZT) and Lead – Magnesium niobate Lead titanate (PMN-PT). 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 commercial 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 0.2 fF to 10 fF. Sets of gold circular pads of different diameters (100 nm to 3μm) have been deposited on the PZT and PMN-PT thin films to define capacitances in the range 10 aF – 30 fF. The samples are placed very close to the calibration kit under the SMM tip so that the capacitances are measured by the calibrated SMM while preserving its calibration data. The measurements have been performed on these piezoelectric materials at a single frequency of 3 GHz without applying DC bias voltage. A complete uncertainty budget has been drawn up leading to a combined relative uncertainty in the order of 10 % (one standard deviation) for measured dielectric constants in the range 100 - 1000.

Resume : Multimodal Scanning Force Microscopy (SFM) is a valuable family of techniques for characterisation of nanomaterials, where complementary sensitivities to physical properties of different modes are combined to separate species within a scan. Here we apply a near-field optical and Kelvin probe microscopy modes to a Van der Waals heterostructure sample. By combining the measurement datasets and applying cluster analysis we are able to reliably distinguish different heterostructure species within the sample, as well as providing larger datasets for improved statistical significance in metrological applications of multimodal microscopy. We study the effect of contact engineering by adding a graphene buffer layer to a vertical metal-TMD contact. Multimodal SFM techniques are employed in a combinatorial manner to locally study the influence of a graphene buffer layer on the contact resistance, compared to neighboring regions without graphene.

Resume : Hole-selective passivating contacts are used as an effective strategy to decrease recombination losses in c-Si solar cells. Our research deals with high thermal budget contacts: thin interfacial silicon oxide (SiOx) and a boron-doped Si-rich SiCx layers on Si wafer are annealed at temperatures above 750°C. During annealing, thin SiOx layer may disrupt, while SiCx layer partially crystallizes. Optimal performance of the contact is achieved with annealing temperature around 850°C [1]. To explore the transport mechanism through the contact we performed a series of C-AFM tomography [2] measurements. 3D current map of the sample layers can be constructed from consecutive scans with large force applied to the AFM tip, removing the material during the measurement. This enables us to directly visualize the 3D reconstruction of the charge carrier transport through the selective contact. C-AFM tomography reveals conductive channels spanning vertically through the sample starting from interfacial SiOx going up to the sample surface. We report that the density of these conductive channels is not affected by the SiOx thickness, but rather by the annealing temperature and the SiCx layer crystallinity. Visualisation of the charge carrier transport paths offers the direct explanation of the optimal performance of the contact annealed at 850°C – oxide layer remains sufficiently compact to passivate the Si wafer, while the crystalline conductive paths in SiCx layer act as the local electrical contacts. [1] G. Nogay et al., ‘Crystalline Silicon Solar Cells With Coannealed Electron- and Hole-Selective SiCxPassivating Contacts’, IEEE Journal of Photovoltaics, vol. 8, no. 6, pp. 1478–1485, Nov. 2018, doi: 10.1109/JPHOTOV.2018.2866189. [2] U. Celano et al., ‘Conductive-AFM tomography for 3D filament observation in resistive switching devices’, in 2013 IEEE International Electron Devices Meeting, 2013, pp. 21.6.1-21.6.4, doi: 10.1109/IEDM.2013.6724679.

Resume : Many of the Scanning Probe Microscopy methods are based on the probe-sample contact formed under load. Mechanical contact is used in all the nano-mechanical scanning regimes to determine the local mechanical properties of the sample. It is also used in heat or electron transport based methods, like Scanning Thermal Microscopy or Conductive Atomic Force Microscopy. Different variants of these methods and/or their combinations are available in commercial instruments, however, treatment of the contact formation and evolution is still one of the most problematic uncertainty components when such measurements are being made in a quantitative way. In this contribution the aspects of probe-sample elastic deformation in different Scanning Probe Microscopy configurations will be studied both experimentally, using a microscope combined with traceable length and force sensors, and numerically, using Finite Element method and a fast mass-spring model implemented on a graphics card. The uncertainties related to the probe-sample contact formation will be evaluated and a guidance for their estimation from measured data will be given.

Resume : Nickel coarsening is a significant factor for solid oxide fuel cells (SOFC) performance degradation. However, the segmentation accuracy of the nickel phase still needs to be improved when the traditional image-based methods are employed due to the complexity of the material images. In recent years, deep learning methods have shown great advantages in the field of natural images, while the application in nanomaterial images of solid oxide fuel cells has been rarely reported. In this paper, a novel adaptive segmentation network based on deep learning is proposed. The proposed model can dynamically assign weights for the features from different scales, and achieve the self-adaption segmentation of nickel phase finally. Experimental results verify the advantage of the proposed method over comparison methods. Keywords: deep learning, nickel phase, solid oxide fuel cells

Resume : Investigating the same regions of interest of a sample with different instruments has for long been recognized as a very useful approach in various scientific fields. This presentation presents an original solution to spot the same points of interests on different microscopes with a high degree of accuracy and simplicity. It is based on small patterned tags fixed on the samples or their substrates. The patterns include an imaged-based position sensing technology, for which an image of a small part of the tag can be automatically interpreted into absolute coordinates and angular orientation. Taking a single snapshot on the tag with an imaging instrument provides the correspondence between sample and moving stage coordinates. Co-localized observations performed with scanning electron microscopes, optical microscopes and Raman microscopes are presented. Accuracy is in the few μm up to 20 μm range, which is generally sufficient to remove any ambiguity between the observed objects. The different contributions to colocalization errors are investigated experimentally. It is shown that the errors related to the tags are negligeable and that the main source of error is related to the accuracy of the moving stage integrated in the microscopes. An estimator of the relocalization error can be obtained in a straightforward way. This solution is believed to save time to researchers and facilitate cooperation between laboratories.

Resume : The potential applications of nanoparticles in modern technology are numerous, across a broad range of potential fields such as optoelectronics, catalysis, medical imaging and therapeutics, and many others. However, for such applications to be brought out of the lab and into real-world use it is imperative that the behaviour and properties of such nanoparticles can be reliably understood – this is especially true in fields with strong regulatory requirements, as is the case for medical applications. Accurate characterisation of nanoparticle systems is therefore a priority. Many current potential nanoparticle-based devices and products rely on quite complex systems – rather than simple, spherical particles of a single material, core-shell or core-multi-shell systems are common. Furthermore, such systems may not form in the perfectly symmetrical, concentric shell structure they are often idealised as having. Instead, off-centre cores and incomplete shells are a common occurrence. Surface analysis techniques such as X-ray Photoelectron Spectroscopy, which provides quantitative information on sample chemistry from depths of up to ~10 nm, are ideally suited to the analysis of core-shell nanoparticles, whose coatings are commonly around this length scale. However, analysis of topographic, layered, and other such complex structures using XPS is non-trivial, and requires careful consideration combined with appropriate supporting information regarding the expected structure Here we discuss the surface analysis of two forms of non-ideal nanoparticle morphologies, consisting of polytetrafluoroethylene (PTFE) cores coated with either polystyrene (PS) or polymethylmethacrylate (PMMA). Both of these systems form core-shell particles whose coatings are not concentric around the core, and in the case of the PS-coated particles, incomplete. A complete understanding of the XPS data is obtained by the use of a suite of appropriately chosen analytical techniques, including electron microscopies and solution-based size and density measurement techniques (dynamic light scattering, DLS, and differential centrifugal sedimentation, DCS). Simple numerical modelling of the expected XPS intensities is shown to give good agreement with the experimental results. Further, we discuss the use of Argon-cluster sputtering as a means of elucidating the internal structure of the PMMA-coated particles, and demonstrate an effective model for the analysis of the resulting XPS intensities.

Resume : For high-resolution electron microscopy of 2D materials, it is vital to have atomically clean sample surfaces. Established cleaning methods such as ex-situ heat treatments often leave a layer of contamination on the surface and can also cause damage. So-called pre-situ methods were recently developed for cleaning samples using radiative or laser heating in the same vacuum system as an aberration-corrected scanning transmission electron microscope (STEM), causing less damage and producing cleaner surfaces [1]. To further enhance the laser cleaning of graphene and other 2D materials, we have developed a far-field laser system with focusing optics for irradiating a sample in-situ while it is observed with STEM. In addition to enabling finer control over the cleaning process, laser irradiation activates photon-induced electron energy loss and gain processes that may be spectroscopically accessed to study plasmons and other electronic properties [2]. [1] Tripathi, M. et al. Cleaning graphene: Comparing heat treatments in air and in vacuum. physica status solidi (RRL) – Rapid Research Letters 11, 1700124 (2017). [2] Das, P. et al. Stimulated electron energy loss and gain in an electron microscope without a pulsed electron gun. Ultramicroscopy 203, 44–51 (2019).

Resume : By far most of the current nanoparticle (NP) research is dealing with (quasi-) spherical and/or monodisperse particles. However, many NPs used in industrial applications are rather aspherical and polydisperse. This inhomogeneity considerably hampers their characterization and, particularly, the accurate determination of the nanoparticle size. In order to overcome this problem and to promote the availability of standardized size measurement methods, it is crucial to develop and establish (candidate) reference materials with inhomogeneous size (distribution), aspherical shape as well as agglomerated or aggregated particles. Therefore, a new set of NPs including Au-, SiO2 , and TiO2-particles is investigated. The range of properties comprises polydisperse spherical, bimodal spherical, rod-like, acicular, bipyramidal, sheet-like as well as cubic NPs. With respect to a good traceability of the measurements, size and size distributions of the candidate reference materials are determined using microscopic methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning electron microscopy in transmission mode (STEM-in-SEM), atomic force microscopy (AFM) as well as small angle X-ray scattering (SAXS) as an ensemble technique. The development of protocols for sample preparation is of particular importance to obtain a homogeneous dispersion of the NPs on a substrate. Further, approaches for signal modelling for all the methods above are being developed. The initiation of two VAMAS (www.vamas.org/twa34/index.html) inter-laboratory comparisons on bipyramidal titania and bimodal silica with different modal concentration ratios will also be highlighted. This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union?s Horizon 2020 research and innovation programme.

Resume : The wide use of nanoforms with at least one dimension below 100 nm in our daily life requires a detailed knowledge of their physicochemical properties which are needed for risk assessment or quality control. Therefore, a comprehensive characterization of these properties was considered as relevant including: chemical composition, crystallinity, particle size, particle shape, surface chemistry, and specific surface area (SSA). We want to discuss, how Scanning Electron Microscopy (SEM), Electron Probe Microanalysis (EPMA) in the version with energy dispersive X-ray spectroscopy (EDS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) can contribute to gain comprehensive insights into the nature of the nanoparticles. SEM results provide the particle size and shape (distribution). A quick identification of the main chemical elements present in the sample can be obtained with EDS, whereas XPS allows a more detailed chemical identification of the small nanoparticles below 20 nm or of the near-surface region of larger particles. ToF-SIMS is even much more surface-sensitive and leads to a deeper understanding of the surface chemistry of the nanoparticles. As exemplary samples, two Al-coated TiO2 samples in nanopowder form were chosen from the JRC repository, capped either with a hydrophilic or a hydrophobic organic shell. A focus of our case study was to show, how reliable, reproducible and traceable data can be obtained. Therefore, each step in the workflow of sample investigation must be described in detail. For the most of these steps, well-established standards are available. Usually, the conditions of the particular measurements with each analysis method are saved as meta-data in the common file formats. But other factors like sample preparation and data reduction approaches may influence the result of the investigations in a significant manner and must be described often in a separate file (as a protocol) together with the data file. For sensitive materials like nanoobjects, the preparation of the sample influences the results crucially, e.g. measured as suspension or as powders. Furthermore, data reduction like selection of relevant peaks in spectra or particles in images, background subtraction, peak deconvolution, models for the quantification of the spectra must be considered in the interpretation of the results ideally with associated individual measurement uncertainties. Only a detailed description of all these factors allows to obtain a comprehensive characterization with reliable, reproduceable and traceable data. Examples of standardized procedures of measurement or on data reduction will be highlighted. We thank for the funding from the European Unions’s Horizon 2020 for the project NanoSolveIt (grant agreement No. 814572) and for the project NANORIGO (grant agreement No. 814530).

Resume : Transmission Electron Microscopy (TEM) has been widely used on particles size distribution characterization, particularly with nanostructured samples and in cases that require complementary high-resolution techniques – such as chemical mapping or localized diffraction analysis. Among the numerous applications examples are the quality control on catalysts synthesis and the metallic alloys development by precipitates optimization. Traditionally, particles size distribution characterization with TEM involves lengthy imaging experiments to support a fair statistical representation of the sample, and extensive image analysis for features identification and measurement. For this reason, TEM is often regarded as an ineffective and expensive approach for the purpose and only recommended in case alternative techniques such as Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) techniques and Dynamic light scattering (DLS) are not applicable. This presentation features recent instrumentation advances that allow for automated TEM imaging and chemical mapping experiments, and simultaneous data analysis by customizable algorithms for flexible features detection. Results indicates successful unattended TEM imaging experiments and data analysis with high yield (>6000 particles / 10 minutes), and advanced nanoparticles characterization by combining scanning TEM (STEM) imaging, X-rays Energy Dispersive Spectroscopy (EDX) mapping, and Artificial Intelligence (AI) data analysis methods already integrated to an easy-to-use workflow.

Resume : The desire for next generation lithography techniques for patterning of structures on the single digit nanometer scale has never been stronger. One promising approach for the creation of structures with features in the regime of 10 nm is block-copolymer (BCP) self-assembly. Here a BCP separates in microphase domains consisting of blocks of each individual polymer. After selectively removing one of the blocks a mask is obtained which can be used for further lithographical processes. The quality of patterns obtained, e.g. the roughness of features, strongly depends on the abruptness of nanodomain interfaces, which therefore needs careful characterization. X-ray and neutron scattering techniques typically used for this purpose give spatially averaged information, while scanning probe techniques are limited in lateral resolution. So far transmission electron microscopy (TEM) has been used mainly after staining of one of the phases for contrast enhancement, making the results depending on the infiltration of a metal salt. Here we show that by utilizing advanced analytical (scanning) transmission electron microscopy ((S)TEM) techniques at low acceleration voltages, the contrast between microphase separated polystyrene (PS) and polymethylmethacrylate (PMMA) can be enhanced without staining. We use high-resolution (S)TEM, energy-filtered TEM (EFTEM), EFTEM spectroscopic imaging (SI) and electron energy loss spectroscopy (EELS) to study the microphase separation in thin films of both cylinder- and lamellae-forming PS-b-PMMA BCPs. BCP membranes are prepared for the TEM after microphase separation on a sacrificial SiO2 layer by HF etching and skimming of the BCP film with a gold TEM grid. We demonstrate that using an acceleration voltage of 60 kV one can clearly observe the domain morphology and size, allowing to characterize the interfacial width and roughness (line edge roughness) at less than 1 nm resolution. EFTEM thickness mapping enables to visualize local material densities within the BCP films, giving insights into the internal structure of nanomask defects, i.e. deviations from the periodic order of microphase domains. Using EFTEM elemental mapping the volume fraction of non-phase separated polymer species is determined. The difference in low-loss EEL spectra of PS and PMMA are exploited to identify the two different polymers in EFTEM-SI image series. Thus, advanced analytical (S)TEM gives new insights in the microphase separation of BCPs and helps to improve the patterning quality obtained by BCP lithography.

Resume : The groundbreaking work in 2004 leads an unprecedented boom in interdisciplinary researches for 2D materials. Due to superior properties, 2D materials promise tremendous potential applications in electronics, optoelectronics, membranes, energy storage and generation, catalysis, sensing and so on. Silicene, a monolayer of silicon atoms arranged in a honeycomb lattice, is excellently compatible with the materials used in today?s semiconductor manufacturing. In this study, silicene-terminated CaSi2 was cleaved inside a TEM using an in-situ manipulator. HRTEM studies on a standard lift-out lamella performed from several crystallographic orientations confirmed the cell parameters of a = 3.7 Å and c = 30.60 Å, and allowed to determine its exact orientation in the SEM/FIB system. A FIB procedure with corrected tilting and rotating angles has been developed to ensure that the tensile force applied by the manipulator is perpendicular to the (0 0 1) plane, and that the [1 0 0] pole axis could be used for HRTEM imaging. A sharp and flat cleavage interface with a length of more than 1 µm was observed in one in-situ experiment. HRTEM images from multiple regions confirmed that the flat cleavage followed the (0 0 3) plane of the CaSi2 crystal. The current in-situ study demonstrates that a surface sheet with silicene-like atomic arrangement can be mechanically exfoliated from silicide compounds.

Resume : Grazing-Incidence X-ray fluorescence analysis is a very powerful technique for the in-depth analysis of many types of technologically relevant samples, e.g. nanoparticle depositions, shallow dopant profiles or thin layered samples. However, the extraction of the depth dependent information about the sample is usually based on a modelling of the experimental data. This requires a profound knowledge on the geometrical parameters of the employed setup, especially the incident beam as well as the detector aperture parameters. Together they determined the incident angle dependent so-called effective solid angle of detection which must be known in order to model any experimental data set. In this work, we demonstrate how the instrument parameters, which determine the effective solid angle of detection can be determined using a well-known calibration sample for a Bruker S4 T-STAR instrument.

Resume : As functional devices in many areas of application steadily get smaller and require material systems not only at the microscale but nanoscale, the demand for analytical high-resolution methods is increasing in the same manner. X-ray spectroscopy (XRS) is a nondestructive technique widely used to qualitatively and quantitatively characterize material systems. However, vibrations with amplitudes in the order of the desired resolution, caused from the surrounding environment, may disturb any resolution sensitive measurement. We present a novel instrumentation for synchrotron radiation based scanning XRS, where all relevant optical elements are mounted on a single platform. This compact setup minimizes vibrations, enabling a spatial resolution in the nm regime with scanning transmission X-ray microscopy (STXM) and scanning X-ray fluorescence analysis (XRF). Both emitted fluorescence radiation and transmitted radiation are detected with calibrated X-ray detectors. We demonstrate a reference-free quantification method based on XRF on a nanostructured germanium sample. To determine the mass deposition of germanium, the lateral size of the incident beam has to be known. In initial experiments we achieved a beam with full width at half maximum of about 100 nm, which is in line with the probed sample dimensions.

Resume : The increasing demand for secondary electrochemical storage devices requires well characterized and working battery systems. Each battery suffers from degradation effects which lead to capacity fading and life cycle reduction. The single mechanisms vary for different types of batteries. With electrochemical methods the fading can easily be monitored, but to understand the underlying chemical and physical properties which are responsible for the capacity reduction further analytic techniques are needed. We demonstrate the possibilities offered by X-ray spectrometry to investigate degradation mechanisms for an exemplary Lithium-Ion battery (LIB). We present how X-ray fluorescence analysis (XRF), near edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) can contribute to a deeper insight by explaining which information each method can reveal about the cell?s properties. The element of interest is manganese since the cathode material consists of lithium nickel manganese cobalt oxide (NMC). The combination of the different methods generates a clearer understanding of the chemical processes in the battery and can therefor help to improve the performance by using enhanced material combinations.

Resume : We will present a calibratable and compact high energy resolution wavelength-dispersive spectrometer based on the von Hamos geometry for XES and RIXS in the photon energy range from 2.4 keV to 19.0 keV. Using one or two full-cylindrical highly annealed pyrolytic graphite crystals as dispersive elements, the measurements can be either optimized towards a large solid angle of detection resulting in high detection efficiency or towards an optimized resolving power. The chemical speciation capability of the device is demonstrated on the basis of different transition metal compounds. The calibration of the instrumental response of the presented wavelength-dispersive spectrometer enables an accurate determination of binding state related structures in X-ray spectra, thus enabling reliable identification and discrimination capabilities in combination with calculations based on the OCEAN code. Furthermore the calibratability of the experimental setup was made profit of to determine L-shell atomic fundamental parameters of gadolinium.

Resume : Porous silicon-based nanoparticles (PSi NPs) exhibit good biodegradability properties and are currently quite promising objects for potentially wide application in various biomedical usage, including theranostic applications, antibacterial and antiviral therapy, etc. The drying process and surface pretreatment strongly affect the dissolution rate of PSi NPs in model fluids and living cells. Two types of PSi NPs were obtained: subjected to air drying (AD-PSi NPs) or freeze drying (FD-PSi NPs). AD- and FD-PSi NPs were 1-10 µm agglomerates of 100-nm PSi particles according to the SEM images. Highly intensive synchrotron radiation of Kurchatov synchrotron was used to study the specificity of electronic structure, phase composition and local atomic surrounding specificity of AD- and FD-PSi NPs. X-ray Absorption Near Edge Structure and X-ray Photoelectron spectroscopy were used as analytical techniques. The analysis of the surface physical and chemical state of AD- and FD-Psi powders based on synchrotron data obtained showed, that the freeze-drying process prevents the deep oxidation of the surface of silicon nanocrystals. The results obtained indicate a significant effect of drying processes on the surface properties of PSi NPs, which is important for their long-term storage and further use as therapeutic agents. The study was supported by Russian Science Foundation (Project 19-72-20180).

Resume : Copper nanostructures (CuNSs) with highly developed surface are potentially perspective functional material for biosensoric application as plasmon-active surfaces for amplification of the Raman scattering signal. Swift heavy ion track technology has been used for the pre-patterning of surfaces for self-organized localized CuNSs growth in porous matrix. Wet-chemical electroless approach for the localized formation of the CuNSs in pores have been applied. According to scanning electron microscopy data, observed tracks in the silica matrix have been partially filled by two types of copper nanocrystals with the grain dimensions of 10 nm and 70 nm as mean sizes. The samples with different pores filling degree have been investigated. First type of surfaces is related to the partly filled pores by Cu and the second type to overfilled pores with spherical copper caps formation on a top. For a careful and detailed analysis of the observed surface atomic and electronic structure as well as physico-chemical state the X-ray Absorption Near Edge Structure (XANES) using large-scale facilities at BESSY II synchrotron storage ring at HZB Berlin have been used. Noticeable changes of electronic structure and phase composition caused by transformation of crystal sizes and filling degree have been detected. The detected local copper and oxygen atomic surrounding reconstruction allowed us to establish a validity for used proposed technique for controlled formation of SERS sensitive surfaces.

Resume : In this work, Pt-Ti core-shell nanoparticles (NP) of 2 nm to 3 nm in size and 30000 u ± 1500 u as specified single particle mass, deposited on flat silicon substrates by means of a mass-selected cluster beam source, were used for the investigation of the modification of the X-Ray Standing Wave (XSW) field intensity with increasing NP surface coverage. The focus of the investigation is on the determination of the range of validity of the undisturbed flat surface approach of the XSW intensity in dependence of the actual coverage rate of the surface. Therefore, the nanoparticles were characterized using reference-free grazing incidence X-ray fluorescence analysis (GIXRF) employing radiometrically calibrated instrumentation. In addition, near-edge X-ray absorption fine structure (NEXAFS) measurements were performed to investigate the binding state of titanium in the core-shell nanoparticles which was found to be amorphous TiO2. The combination of GIXRF measurements and of the calculated XSW field intensities allow for a quantification of the core-shell nanoparticle surface coverage. For six different samples, the peak surface coverage could be determined to vary from 7 % to 130 % of a complete monolayer-equivalent coverage. A result of the current investigation is that core-shell nanoparticles modify the intensity distribution of the XSW field with increasing surface coverage. This experimental result is in line with calculated XSW field intensity distributions at different surface coverages using an effective density approach.

Resume : In high-resolution electron microscopy of 2D materials, atomically clean sample surfaces are crucial. Ex-situ cleaning methods one established cause damage and often leave a layer of contamination on the sample. Pre-situ cleaning via heat and laser irradiation in the same vacuum system as an aberration-corrected scanning transmission microscope (STEM) have been shown causing less damage and atomically clean surfaces [1]. We developed a free-space, far-field laser system with external focusing optics for irradiating the sample in-situ while observed in STEM, sharing the same environmental decoupling. Furthermore, the optical return path is used for VIS spectroscopy. In-situ systems with near-field focusing optics using integrated pierced parabolic mirrors have been used for photon-induced electron energy loss/gain specroscopy (EELS/EEGS) an cathode luminescence (CL) studies [2]. In contrast, our modular approach uses an available view-port and leaves the rest of the setup intact. In this work, we elaborate on it's design, focussing optics and operation. [1] https://doi.org/10.1002/pssr.201700124 [2] https://doi.org/10.1016/j.ultramic.2018.12.011

Resume : Multi-Layered Nanocomposite CrN/MoN Thin Films fabricated by magnetron sputtering and by vacuum arc evaporation of cathodes have been studied be several types of X-ray based characterisation techniques. Elemental composition of the surface was studied by energy-dispersive X-ray spectroscopy (EDS) and wavelength-dispersive X-ray spectroscopy (WDS). Additionally, the elemental characterisation has been performed by means of X-ray fluorescence (XRF) and total reflection X-ray fluorescence (TXRF) to compare results and reliability of such techniques, which are not commonly used for hard metal nitride thin films investigation. Multilayer structure of coatings was studied by EDS elemental depth profiling and EDS elemental mapping. Micro- and nanostructure of CrN/MoN coatings was studied by X-ray diffraction (XRD) techniques. Particularly, X-ray reflectivity (XRR) to measure thickness of individual layers and period multi-layered thin films and X-ray diffraction in various geometries to study phase composition, lattice parameters and preferential orientation. As CrN and MoN films have similar crystal structure and lattice parameters, a conventional θ/2θ scan gives broadened peaks on overlapped XRD pattern of two CrN and Mo2N cubic phases. To distinguish individual layers grazing incidence XRD (GIXRD) approach was employed when by selecting a fixed incidence angle in a low range it is possible to get XRD pattern limited by a certain X-ray penetration depth. Based on GIXRD and sin2ψ method the residual stresses and strain for individual layers have been evaluated. In-plane XRD experiments have been performed for analyses of diffraction planes oriented normal to the surface with control of incidence angle to get information from different layers of the multi-layered CrN/MoN coatings. It was shown that many X-ray based characterisation techniques are very helpful and adequate to analyse micro-, nanostructure and elemental composition of multi-layered CrN/MoN thin films: EDS, WDS, XRD, TXRF, XRD, XRR, GIXRD, in-plane XRD.

Resume : Low-energy Ar+ ion irradiation of thin metal films activates a reduction processes accompanied by the decrease of O impurities amount, while the atomic mixing of components and phase transformations do not take place [1]. For that instance, the secondary-ions mass spectrometry (SIMS) technique can be extremely useful for highly sensitive detection of impurities presence at the interfaces and grain boundaries, unlike other analytical methods. This is especially actual in case the different primary ions are applied. In present study, we demonstrate how a combination of positive O+ (1 keV) and negative Cs- (2 keV) primary ions on Ion ToF IV device can be used for investigation of reduction processes in Ni/Cu/Cr tri-layers after ion irradiation with the beam energy of 400-2000 eV. The signal intensity of main components depends on the amount of O atoms in these layers. Moreover, when the primary O+ ions are used this intensity decreases upon evolution of the reduction processes, whereas for Cs- ions it increases. It is attributed to different values of the ionization potentials (Cs reveals the lowest value (-3.9 eV) among all elements) and the work function of the matrix electrons. Application of Cs- primary ions could significantly increase the sensitivity to the O detection, since Cs is a chemically active metal with high affinity to O. It was found that, e.g. after irradiation with an energy of 600 eV for 30 minutes, the intensity of Ni secondary ions has a clear periodicity of maximums and minimums that completely fits to a similar signal from O ions. It indicates that the reduction processes occur inhomogeneously through the film depth. Most likely, O atoms are mainly released from the grain boundaries upon ion irradiation.

Resume : In the last decades, technologically relevant nanostructures e.g. transistors got smaller, more complex, and multi-dimensional. Along with these developments, an increasing need for metrology techniques able to characterize such nanostructures is developing. Grazing Incidence X-ray fluorescence Spectrometry (GIXRF) has already been shown to be capable of characterizing such regular ordered nanostructures with respect to their dimensional and compositional parameters [1,2,3]. However, in GIXRF the footprint of the incident beam is too large for the small periodic test structure fields on state-of-the-art semiconductor dies. Here, Grazing Emission X-ray Fluorescence Spectrometry (GEXRF) can be beneficial as it does not require the shallow incident angles and thus can be performed using much smaller beam footprints on the sample surface. As GE- and GIXRF are directly linked, similar information is expected to be retrievable from GEXRF measurements of the nanostructures. This work aims to evaluate and demonstrate the applicability of the GEXRF spectrometry technique for the dimensional and compositional characterization of such nanostructures. 1. V. Soltwisch, P. Hönicke, Y. Kayser, J. Eilbracht, J. Probst, F. Scholze, B. Beckhoff, Nanoscale (2018) 10, 6177 2. K. V. Nikolaev, V. Soltwisch, P. Hönicke, F. Scholze, J. de la Rie, S. N. Yakunin, I. A. Makhotkin, R. W. E. van de Kruijs, F. Bijkerk, J. Synchr. Rad. (2020) 27, 386 3. P. Hönicke, A. Andrle, Y. Kayser, K.V. Nikolaev, J. Probst, F. Scholze, V. Soltwisch, T. Weimann, B. Beckhoff, Nanotechnology (2020) 31, 505709

Resume : Low energy Electron Energy Loss Spectroscopy has been employed for investigation of the electronic states of amorphous and crystalline Fe73.6Cu1Nb2.4Si15.8B7.2 alloy surface and alloy components. This amorphous alloy with a nanocrystalline grain structure, known as FINEMET, is a very attractive soft magnetic material since it exhibits excellent permeability even in a high frequency range. Such a type of materials is prepared from a melt-spun amorphous material by annealing at temperatures higher than the crystallization temperature. Usually, FINEMET consists of ultra-fine grains of size a few nanometers, which has been thought to cause the soft magnetic properties. Electron energy loss spectroscopy (EELS) is a powerful surface analytical technique which can be used to obtain physical-chemical state information as a function of the probing depth by varying the primary electron beam energy E0. EELS is very sensitive to the chemical state, and the atomic and electronic structure of the near surface region of the solid. Generally, EELS data relate to the characteristic electron losses which occur due to inter-band and intraband electronic transitions, ionization losses and surface and bulk plasmons. Amorphous ribbons, about 25 µm thick and 10 mm wide, were prepared by a single-wheel melt-spinning technique. EELS peak-to-peak amplitude of the differentiated signal was obtained with a lock-in amplifier with 1- 2 V modulation voltage. The energy resolution of the analyzer was ?E/E = 0.1- 0.3% for energies E0 < 650 eV The EEL spectra for the pure alloy components: Fe, the amorphised Si wafer, B, Nb, Cu and amorphous Fe81B7Si1P10Cu1 alloy (free surface) for the primary electron beam energies E0 ranging from 150 to 650 eV were measured . In the EELS spectra, we selected the following types of characteristic losses: inter-band and intra-band transitions, surface (Es) and bulk (Eb) plasmon, excitations and their hybrid modes. The following values of the plasmon energy for amorphous alloy were obtained (eV): Es = 15.2; Eb = 24.2. It was shown that for the amorphous alloy the measured spectra have a complicated structure, but are similar to the spectra of Fe. The measured energies for the plasmon excitations were found not to agree with calculated values according to the classical theory for the collective oscillations in solids. for all specimens changes in the intensity energy Es and Eb were observed depending on primary electron energy. With an increase in the energy of ??? primary electrons, a decrease and an increase in the intensity of ??? surface and bulk plasmons is observed, respectively.

Resume : X-ray spectroscopy is a powerful family of non-destructive characterization techniques to study the electronic and local structure of matter, with diverse applications in chemistry, physics, biology, and materials science. X-ray reflectivity (XRR) is a surface-sensitive analytical technique used to characterize surfaces, thin films and multilayers. Grazing incidence x-ray fluorescence (GIXRF) is an analysis technique that uses the angle-dependent x-ray fluorescence (XRF) emitted by near surface atoms consecutively to the excitation at glancing angles. Thus, XRR is more sensitive to the electronic density, and GIXRF is sensitive to element density. Therefore, combining these two techniques leads to better accuracy compared with one technique alone. It is well known tkat the most intense x-ray lines (K lines) are not singlets. The Kalpha is a doublet and the Kbeta is a multiplet. The standard separation of the Kalpha1 and Kalpha2 lines is a few eV and the intensity ratio is approximately 2:1. Concerning low energy x-rays (~2keV), the L lines are not correctly separated with energy-dispersive detectors (EDS) which makes it difficult to deconvolute the spectra. Moreover, some line displacements due to the chemical environment of the atom can give useful information. Therefore, in order to be able to separate the emission lines, a highly dispersive spectrometer is necessary. The compact von Hamos spectrometer is a high-resolution spectrometer of an easy to handle format. In this geometry, the principal elements are the effective x-ray source, defined by the illuminated spot on the sample, a flat crystal with high reflectivity and a charged coupled device (CCD) camera. The camera is placed parallel to the crystal, on the same axis as the point source, so that the x-ray reflected by the crystal will reach it according to the Bragg law. The energy range and the resolution are defined by the distances between the source, the crystal, the CCD camera and by the pixels' size. The goal of this work is to develop a wavelength dispersion spectrometer (WDS) based on the compact design of a von Hamos spectrometer (1), dedicated to combined XRR-GIXRF analysis in CASTOR (Chambre d?Analyse Spectrométrique en transmission ou en réflexion) which is located at the Metrology beamline of the SOLEIL synchrotron (2). We will present a first prototype and the experimental validation of the chosen geometry, crystal and CCD camera. References 1. Shevelko, A. P., Kasyanov, Y. S., Yakushev, O. F., and Knight, L. V., Compact focusing von Hamos spectrometer for quantitative x-ray spectroscopy, Review of scientific instruments, V. 73, No. 10, 2002, pp. 3458?3463. 2. Ménesguen, Y., Boyer, B., Rotella, H., Lubeck, J., Weser, J., Beckhoff, B., Grötzsch, D., Kanngießer, B., Novikova, A., and Nolot, E., CASTOR, a new instrument for combined XRR?GIXRF analysis at SOLEIL, X-Ray Spectrometry, V. 46, No. 5, 2017, pp. 303?308.

Resume : To keep up with Moore?s law, the semiconductor industry continues to push the envelope in developing smaller and better-performing devices. Advanced EUV lithography and area-selective deposition (ASD) gain interest because they allow to produce devices with nanometer dimensions. Besides, new materials are being introduced such as ruthenium as a future interconnect or hard mask material. A critical issue for the acceptance of ASD for this application is the availability of adequate process metrology in particular considering the reduced dimensions of the devices. Rutherford backscattering spectrometry (RBS) provides unique quantitative analysis capabilities for such applications tough it is normally not associated with the analysis of very fine features. In this work we demonstrate, for the model case of Ru ASD on a TiN base layer in trenches between SiO2 fins of 30 nm width, that a judicious choice of analysis conditions combined with advanced data treatment can overcome the spatial limitations usually associated with RBS. The challenge for RBS for such applications is that the probing beam would need to be focused to a dimension smaller than the width of the structure (< 10 nm) which is technically extremely difficult to realize. Moreover, the strongly reduced signal intensity would prohibit any statistically relevant analysis. To overcome these limitations, we present an approach termed ?Ensemble RBS? whereby we use a macroscopic (1 mm2) beam to probe a large ensemble of nanostructures. The data will thus represent an average of all these devices but does overcome the spatial resolution and sensitivity limitations. The challenge in this approach is to deconvolute the contributions from the various regions of the sample to derive total areal coverage, considering the morphological aspects (pitch, dimensions, etc.). In our approach, firstly, the analysis of the usual normal-incidence-exit RBS spectrum allows to determine the average areal density of Ru. Secondly, we demonstrate that in off-normal experiments the Ru on top of the fins vs Ru in the trenches can be separated based on their differences in energy loss. In other words, RBS allows to quantify the selectivity for ASD on 30-nm-wide fins. Thirdly, by interpreting the energy loss observed in the substrate signal in off-normal experiments, we determine the pitch of the nanostructures. Besides, it is possible to determine the width-to-pitch-ratio and height of the fins from the energy-loss observed on the signal obtained on titanium and/or the substrate. In conclusion, we demonstrate that ensemble RBS provides a unique step forward in quantitatively characterizing area-selective deposition on nanostructures with high sensitivity and virtually no restrictions on devices dimensions. Further developments are ongoing to reach a true 3D tomographic analysis using RBS for such devices.

Resume : Graphene is one of the most commonly characterized 2D materials, especially in devices such as transistors, sensors and optical waveguides. Among current technological challenges is graphene?s sensitivity to adsorption. Discontinuities appearing in graphene make its surface prone to adsorb pollution from the atmosphere, which affects graphene?s doping level and deteriorates its transport properties. To reduce the influence of the environment on the properties of graphene, it is necessary to apply a thin layer with a protective function. One possibility is to cover graphene with a thin layer of Al2O3. This research presents how the aluminium oxide layer, obtained by ALD (Atomic Layer Deposition), changes the electrical and structural properties of epitaxial CVD graphene on SiC. For this purpose, a thorough analysis of the material was performed using Raman Spectroscopy and Hall-effect measurements. Also, a comparative analysis of various characterisation methods of the oxide layer was presented, allowing for precise determination of the thickness and composition of the material (including Spectroscopic Ellipsometry, X-ray Reflectrometry, Secondary Ion Mass Spectrometry, Scanning Electron Microscopy). It has been determined which of the presented methods are the best solution for the characterisation of this type of materials. Acknowledgements: This work was supported by the Research Foundation Flanders (FWO) under Grant no. EOS 30467715 and the National Centre for Research and Development under Grant Agreement No. LIDER 0168/L-8/2016 for project ?Graphene on silicon carbide devices for magnetic field detection in extreme temperature conditions?. Karolina Pi?tak acknowledges financial support from IDUB project (Scholarship Plus programme).

Resume : Currently, one the most forward-looking directions of improving the efficiency of nitride-based optoelectronic devices is the introduction of spatial nitride structures, such as nanowires. Indeed, these type of structures enlarge the active surface for optical phenomena as compared to conventional nitride structures. On the other hand, nanowires are troublesome to control. Another solution considered for possible efficiency improvement is the use of a transparent conductive electrode (TCEs). Many scientific reports indicate graphene's significant role as a TCE in intensifying light extraction from nitride optoelectronic structures. In this work, our investigations focus on own patented technology of three-dimensional AlGaN-based microcolumns that are analogous to nanowires. Contrary to the mentioned nanowires, they are stable and stiff, and their shape, length, and distance are controllable. These features enable us to use each microcolumn as an individual optical epistructure that provides a stable substrate for the graphene layer. The aim of this work is to present the investigated impact of the AlGaN-microcolumns on graphene?s behaviour and their potential in novel merged graphene-AlGaN optoelectronic heterostructures. For this reason, AlGaN microcolumns were grown by MOVPE and covered with transferred graphene. The relation between graphene and microcolumns was analyzed by scanning (SEM) and atomic force microscopy (AFM), and Raman spectroscopy. The obtained results showed that there is close dependence between the microcolumns morphology and the properties of graphene. Acknowledgments: This work was supported by the Research Foundation Flanders (FWO) under Grant no. EOS 30467715.

Resume : SAXS CT is a method which allows the measurement of the small-angle X-ray scattering (SAXS) signal from the interior of a sample. The measurement protocol consists of regular SAXS measurements for different angles and positions of the incident beam onto the sample. Similarly to regular absorption CT, the interior microstructure of the sample is reconstructed from these measurements, resulting in a SAXS curve in every voxel. We fabricated a test sample containing the SAXS reference standards silver behenate and microporous silica SBA-15 and compared the SAXS CT data taken at the HZB MX-beamline BL14.1 to regular absorption µCT.

Resume : The enhancement factor (EF), indicating the magnification of the Raman signal of molecules interacting with the surface of plasmonic nanostructures, is a crucial parameter in the field of surface-enhanced Raman spectroscopy (SERS). Metrological calculation of EF requires a careful evaluation of both the signal intensities and the number of molecules in SERS and normal Raman conditions. The determination of the surface density of molecules adsorbed on the substrate is fundamental to estimate the number of active molecules contributing to the enhanced Raman signal on a plasmonic substrate and, for this reason, strongly impacts the estimation of the enhancement factor. A viable methodology for this challenging task is reference-free X-ray fluorescence (RF-XRF). We determined the EF using 7-mercapto-4-methylcoumarin (MMC) as probe molecule on gold-coated silicon nanowires, integrating SERS and normal Raman spectroscopy with synchrotron-based RF-XRF data that provide an absolute quantitative measurement of the molecular surface density [1]. In addition, the surface coverage of MMC on the substrate is modelled by molecular mechanics (MM) and molecular dynamics (MD) simulations. RF-XRF analytical quantification can be extended to other molecules or common analytes for SERS or fluorescence spectroscopy. The adoption of standardized methodologies for the characterization of nanostructured systems promotes inter-laboratory comparison and boosts the applicability and progress of SERS. [1] Cara, E., et al. 2020 Towards a traceable enhancement factor in surface-enhanced Raman spectroscopy. Journal of Materials Chemistry C, 8(46), pp.16513-16519.

Resume : X-ray scattering is one of the older methods for measuring bulk nanostructure in materials, having been around for over 100 years. Theoretically, the technique can quantify inhomogeneities in electron density, where the lengths of the inhomogeneities typically range from 0.1 - 400 nm (with information on lengths between 1 and 100 nm practically easy to obtain). While the measurements are ostensibly straightforward, the resulting scattering pattern is challenging to correct for instrumental effects, and subsequently not easy to interpret. These difficulties, combined with the poor reproducibility and consistency has hindered trust in, and adoption of the method. A consistent methodology, therefore, which is provably reliable for a wide range of samples, is essential for X-ray scattering to achieve more traction in materials science. Over the last years, we have developed just that in a project titled "Methodology Optimization for Ultrafine Structure Exploration", or MOUSE for short. The MOUSE project consists of a methodological and instrumental component to demonstrate its efficacy on practical samples. The comprehensive, near-universal methodology covers the three main aspects of data collection, correction as well as analysis of X-ray scattering. Besides these, however, it also considers necessary aspects of measurement organization and strategies, adequate metadata collection, descriptive data storage in an archival format according to FAIR principles, and instrumental optimization, all to obtain high-quality data. The data corrections in particular are modular, open source, universally applicable, and form a nearly complete set. Their universality has been thoroughly tested both at a collaborating synchrotron beamline as well as in our lab, over an extremely diverse range of samples. The methodology is complete to such a degree that we obtain traceable values by default for both the scattering vector and the absolute scattering cross-section. This in turn means that we can determine the nanostructure dimensions as well as the volume fraction traceably, for example when using our Monte Carlo data analysis method. A mini-large facility was organized at BAM around the MOUSE instrument, where we perform complete sample investigations for fellow scientists from within BAM as well as from external institutes and universities to further test the methodology. This talk will introduce both the methodological as well as instrumental component of the MOUSE project, and highlight some of the practically relevant results from the samples we have measured to date. Future developments will also be discussed as well as the improved symbiosis of the laboratory and synchrotron X-ray scattering efforts.

Resume : Rutherford Backscattering Spectrometry (RBS) is an ion scattering technique used for compositional thin film that are less than 1?m thick analysis. During an RBS analysis, high-energy He2+ ions with energies in the region from several hundred kiloelectron-volts to 2 - 3 MeV are directed onto the sample and the energy distribution and yield of the backscattered He2+ ions at a given angle is measured. Since the backscattering cross section for each element is known it is possible to obtain a quantitative compositional depth profile from the RBS spectrum obtained. This method is unique in that it does not destroy the sample, also it allows quantification without the use of reference standards. The capabilities of this method can be significantly expanded. In particular, the method can be used in powder nanotechnology to study elemental composition in microscopically small objects. The application of methods based on Rutherford Backscattering Spectrometry is extremely interesting for adsorption energy devices, in particular, these methods can be used with maximum efficiency for various chemoelectronic converters. A unique opportunity is to study the elemental surface of adsorbates on the surface phase separation in functional nanostructured layers. For this reason, the preparation of planar-distributed chemoelectronic converters and the study of the elemental composition of adsorbates using the Rutherford Backscattering Spectrometry technique was the purpose for the investigation. The tasks of this study included: development and optimization of the technology for producing planar chemoelectronic converters a functional layer in the form of rounded drops containing monodisperse nanosized (7.5 ?m) particles of a solid solution of the ZrO2 system -3 mol% Y2O3 (YSZ) in the PVA polymer matrix, study of the theoretical characteristics of the obtained chemoelectronic converters, study of the elemental composition of the obtained chemoelectronic converters using Rutherford Backscattering Spectrometry. With the help of nuclear and atomic methods,the atomic and chemical compositions of these layers were investigated. The thickness of the oxide layers was found to be approximately the same for all implanted samples. These values were determined on the basis of Rutherford Backscattering Spectrometry and nuclear reactions (RBS/NR). The study was performed in the scope of the Project H2020/MSCA/RISE/SSHARE number 871284 project

Resume : During the past years there has been a rapid development of various complex nanostructures which led to an emergence of novel type optical elements. These compact and flat elements can control and shape wavefront, can be used in place of conventional lenses or as polarization sensitive devices. The purpose is to design a cluster of nanoparticles which could be used as a single meta-atom for a more complex metasurface. Here, we engineer collective vector response to the polarization of the source beam by using the concept of geometrical phase. In this way we can design such elements as S-waveplates, top hat converters, flat axicons etc. For numerical simulations we use Lumerical's Finite-Difference Time-Domain (FDTD) and T-Matrix methods. We use the T-matrix method which is faster to sweep different cluster parameters, but this method can accumulate rounding errors to a significant level. Therefore we use the Lumerical FDTD software for confirmation and visualization of the results. The parameter space of three nanoparticles consists of dielectric constant, particle radius and inner geometry of the cluster. We analyze and find the optimal values and use such meta-atom for design of a S-waveplate element. We report that the retardance of one layer of meta-atoms is not sufficient for the proper function of the element. Therefore, multiple layers of metaatoms were introduced. By varying the distance between the two layers we have found that the most efficient distance between layers is equal to the wavelength of the incident beam, what is inline with effective retardance. We report that multiple layers produce, in general, a better quality beam, but the overall transmission of the system decreases. By selecting the optimal parameters for our application, we can fine tune the quality and the exit intensity of the beam.

Resume : Graphene and related materials (GRMs) have a wide range of different chemical, electrical and electronic properties which render them useful for technological applications. A major issue hindering large-scale application of such materials on an industrial scale is related to quality control and metrology: researchers and industrial end-users are often confused by the wide range of commercially available graphene products, often with questionable claims of outstanding quality and properties [1]. There is thus an urgent need to develop a graphene metrology based on standard definitions and techniques, allowing valid comparisons between different materials. Here we present a simple, fast and general protocol for quantitative analysis of X-ray photoelectron spectroscopy (XPS) data provides accurate estimations of chemical species in graphene and related materials (GRMs). XPS data are commonly used to estimate the quality of and defects in graphene and graphene oxide (GO)[2], by comparing carbon and oxygen 1s XPS peaks, obtaining an O/C ratio. This approach, however, cannot be used in the presence of extraneous oxygen contamination. The protocol, based on quantitative line-shape analysis of C 1s signals, uses asymmetric pseudo-Voigt line-shapes (APV), in contrast to Gaussian-based approaches conventionally used in fitting XPS spectra, thus allowing better accuracy in quantifying C 1s contributions from graphitic carbon (sp2), defects (sp3carbon), carbons bonded to hydroxyl and epoxy groups, and from carbonyl and carboxyl groups. The APV protocol was evaluated on GRMs with O/C ratios ranging from 0.02 to 0.30 with film thicknesses from monolayers to bulk-like (>30 nm) layers and also applied to previously published data, showing better results compared to those from conventional XPS fitting protocols [3]. Based uniquely on C 1s data, the APV protocol can quantify O/C ratio and the presence of specific functional groups in GRMs even on SiOx, substrates, or in samples containing water. References: [1] Kovtun A., Treossi E., et al., 2DMaterials 6 (2019) 025006 [2] Larciprete R., Lacovig P., et al., J. Phys. Chem. C 116 (2012) 9900-9908 [3] Kovtun A., Jones D., et al., Carbon 143 (2019) 268-275 Acknowledgement: The research leading to these results received funding from the European Union Horizon 2020 research and innovation programme under GrapheneCore2 785219. The XPS instrument was purchased with financial support from the Emilia-Romagna (Italy) regional project POR FES 2007-2013.

Resume : X-ray fluorescence spectroscopy (XRF) is a well-established, non-destructive technique to investigate the elemental composition of a sample. However, it is very limited in its capability to analyze the elemental depth distribution of samples featuring structures, layers or elemental gradients in the nanometer range. Angle-resolved X-ray fluorescence spectroscopy overcomes this limitation by either varying the excitation angle (grazing-incidence XRF) or the detection angle (grazing-emission XRF) [1]. Interference effects due to refraction of the incident (GIXRF) or emitted X-rays (GEXRF) at interfaces, where the optical density changes, enables depth-profiling applications in the range of few nanometers to several hundred nanometers with a sensitivity in the range of 1 nanometer or better. While GIXRF setups are commercially available in the hard X-ray range [2], measurements in the soft X-ray regime may be of interest due to the more efficient excitation of lighter elements and increased sensitivity for nanoscaled structures. Since a coherent excitation beam with little divergence is a prerequisite for soft X-ray GIXRF, this technique is usually applied at large-scale synchrotron radiation facilities. On the other hand, GEXRF relies on self-interference of fluorescence photons and therefore is not reliant on a monochromatic source for the manifestation of interference effects. This way, also laboratory sources like laser-produced plasmas (LPP) may be employed. To avoid scanning the angular range in GEXRF, a 2D-detector like a CCD or CMOS can be utilized in a scanning-free approach to record the variation of the XRF intensity with the angle in a single measurement using a static setup. Single-photon event evaluation is applied to operate the detector in an energy dispersive mode. In this work we present a laboratory GEXRF setup in the soft X-ray range. The radiation source is a highly brilliant LPP [3], driven by an Yb:YAG laser with a repetition rate of 100 Hz and a copper cylinder as target. The produced plasma features bright fluorescence lines at 1078 eV. This radiation is focused and monochromatized by a pair of toroidal multilayer optics. The detector used is a modified Tucsen Dhyana 95 CMOS detector [4]. Its low noise levels and high frame rate of up to 24 Hz lead to both good energy resolution below 1 keV and low measurement times. The spectrometer potential is showcased with the investigation of multilayer mirrors and thermoelectric copper oxide nanofilms. [1] J. Baumann, Y. Kayser, B. Kanngießer, Phys. Status Solidi B, 2020, 2000471. [2] P. Hönicke, U. Waldschläger, T. Wiesner, M. Krämer, B. Beckhoff, Spectrochim. Acta B 174, 2020, 106009. [3] I. Mantouvalou, K. Witte, D. Grötzsch, M. Neitzel, S. Günther, J. Baumann, R. Jung, H. Stiel, B. Kanngießer, W. Sandner, Rev. Sci. Instrum. 86 (3), 2015, 035116. [4] K. Desjardins, H. Popescu, P. Mercère, C. Menneglier, R. Gaudemer, K. Thånell, N. Jaouen, AIP Conf. Proc. 2054, 2019, 060066.

Resume : Epitaxial Chemical Vapour Deposition graphene is an interesting material for possible application in high-temperature electronic components. Raman spectroscopy is an excellent tool to control basic parameters of graphene. Unfortunately, both graphene-related and silicon-carbide-related signals are visible in the range between 1300 and 2800 cm-1. Therefore the graphene spectrum needs to be separated. The problem becomes extremely important when we deal with the statistical analysis of a large measurement map. Solving this problem requires the involvement of an efficient numerical algorithm extracting the graphene part of the spectrum. Quasi-free-standing graphene necessary for the study has been obtained through hydrogen atom intercalation of sole buffer layer epitaxially grown on a semiinsulating vanadium-compensated on-axis 6H-SiC(0001) substrate. Raman spectra of graphene were obtained in a backscattering geometry of the Renishaw inVia confocal microscope using the 532-nm (2.33 eV) line of a continuous-wave Nd:YAG laser and the Andor Newton CCD detector. The laser power was kept at 13.5 mW and the spot size was reduced to 0.3 mm. Large measurement maps were recorded in an area of 20 × 15 µm2 with a step of 0.3 in both dimensions in order to achieve possibly highest resolution. To solve the above mentioned problem, an analytical method was used, which allows to fit a proper multiplier of the intensity of the reference spectrum in order to correctly separate the graphene signal for individual points of the measurement map. The resultant is an efficient analysis of large areas with high resolution, as shown in Figure 1. Acknowledgements: The research leading to these results has received funding from the National Science Centre under Grant Agreement No. OPUS 2019/33/B/ST3/02677 for project ?Influence of the silicon carbide and the dielectric passivation defect structure on high-temperature electrical properties of epitaxial graphene" and the National Centre for Research and Development under Grant Agreement No. LIDER 0168/L-8/2016 for project ?Graphene on silicon carbide devices for magnetic field detection in extreme temperature conditions?. This work has been also partially supported by the National Centre for Research and Development under Grant Agreement No. TECHMATSTRATEG1/346922/4/NCBR/2017 for project ?Technologies of semiconductor materials for high power and high frequency electronics?.

Resume : Accurate defect characterisation of semiconductor materials is essential for development and quality control of devices. A technique that can quickly map and assess wafers to verify quality and select optimum parts of a wafer for subsequent processing is extremely beneficial. However, existing techniques for spatial defect characterisation of semiconductors can be slow or non-quantitative. We propose a new method for defect mapping based on time-resolved photoluminescence (TRPL), compressed sensing and digital light processing (DLP). The spatial resolution achievable with this technique depends upon the optical setup and is diffraction limited at the finest scale, allowing characterisation from the micrometre-scale upwards to wafers and devices, which is a new method for investigating emerging nanomaterials. Applying compressed sensing theory enables the acquisition of spatial information using a single-pixel detector, such as a photodiode. The spatial information is encoded into the excitation beam using appropriate patterns, instead of the traditional point-by-point scan. A simulation procedure has been developed in this work, to investigate the feasibility of this technique and to determine the approach that must be followed to combine compressed sensing with TRPL measurements. The model simulates a pulsed excitation laser source with the beam shaped as pseudo-random spatial patterns projected onto a sample. Conditions are set such that, on average, a photon is detected for every 20 excitation pulses, after a time interval corresponding with the radiative decay time probability distribution assumed for the sample. This process replicates the time-correlated single photon counting technique (TCSPC). The developed algorithm then processes the simulated TRPL information and reconstructs charge carrier lifetime maps, with spatial resolution determined by the projected patterns. The procedure to convert the acquired data to charge carrier lifetime maps is presented. The reconstructed charge carrier lifetime maps in a real application would indicate the distribution of defects within the measured sample. The accuracy and speed of reconstruction were studied for different types of patterns. The simulation results demonstrate that compressed sensing TRPL can accelerate TRPL measurements by at least an order of magnitude without compromising image information. We demonstrate that even by acquiring only 5% of the number of measurements a raster scan would need, a charge carrier lifetime map can be obtained using the proposed method. The results also demonstrate that sparser sensing matrices lead to better reconstruction quality, while excitation intensity and the number of TCSPC pulses can affect measurement speed and results. The proposed characterisation method is expected to lead to more rapid and higher resolution defect mapping and can be invaluable for multiple semiconductor and emerging electronics industries.

Resume : For the realization and dissemination of the new kilogram, Germany?s national metrology institute PTB uses high purity silicon spheres [1]. To determine the mass of such a 1 kg silicon sphere precisely with a relative uncertainty of 14 µg [2], the mass of the surface layer has to be measured by a traceable technique with an uncertainty of less than 30 ng/ cm2. For the quantitative surface characterization of such a monocrystalline silicon sphere PTB has constructed and taken into operation an analytical instrumentation, which combines X-ray fluorescence and X-ray photoelectron spectroscopy techniques [3]. The main objective of this instrumentation is the characterization and quantification of the oxide layer, which is in the order of a few nanometers, and unintentional contaminations, e.g. by hydrocarbons [4]. The quantification is traceable to reference-free XRF by means of calibration samples with thin silicon oxide layers which are regularly qualified by synchrotron radiation based XRF measurements [5]. Applying complementary X-ray methods for quantitative surface characterization allows for minimizing the influence of the surface on the total uncertainty budget for the determination of the silicon sphere?s mass. In this poster we will focus on the quantification scheme with a reliable uncertainty budget measuring the surface of a silicon sphere for the realization of the new kilogram. [1] G. Bartl, et al., A new 28Si single crystal: counting the atoms for the new kilogram definition, Metrologia (2017) 54, 693-715, doi:10.1088/1681-7575/aa7820 [2] M Stock, et al., Report on the CCM key comparison of kilogram realizations CCM.M-K8.2019, Metrologia (2020) 57, 07030, doi: 10.1088/0026-1394/57/1A/07030 [3] M. Müller,et al., Quantitative surface characterization of silicon spheres by combined XRF and XPS analysis for the determination of the Avogadro constant, Metrologia (2017) 54, 653-662, doi:10.1088/1681-7575/aa73c5 [4] E. Beyer, et al., Investigation of a cleaning procedure for silicon spheres used in the realization and dissemination of the redefined kilogram via combined spectroscopic and gravimetric measurements, Int. J. Metrol. Qual. Eng., 11 (2020) 18, doi: 10.1051/ijmqe/2020016 [5] P. Hönicke, et al., Determination of SiO2 and C layers on a monocrystalline silicon sphere by reference-free X-ray fluorescence analysis, Metrologia (2017) 54, 481-486 doi:10.1088/1681-7575/aa765f

Resume : HfO2 is an important thin film dielectric material in silicon semiconductor technology, and the metrology of the thin film thickness is technologically crucial. Therefore the SAWG (Surface Analytical Working Group) of the CCQM (Consultative Committee for the Quantity of Material) approved a Pilot Study (P-190) to establish a metrologically secure measurement method for this quantity. The Report of P-190 has now been agreed between the participants [1], with a Key Comparison (KC-157) to follow. P-190 is similar to the previous CCQM Pilot Study (P-84) for native oxides on silicon [2], with the difference that the metal in the oxide is easily distinguished from the substrate, making RBS a favourable analytical technique. Participants in P-190 used MEIS, XRR, XPS, TEM, SE and RBS [3]. Thickness was measured in length units (nm) by XRR, TEM, and SE; also by MEIS and XPS which were calibrated against traceable XRR. Traceable thickness measurements in units of quantity of material (atoms/cm2) were only available by RBS [4], confirmed by XRR estimates of material density. It turned out that the thin film HfO2 had about 80% of the bulk density, therefore RBS is required to adequately characterise the material. Traceably accurate RBS [5] and EBS measurements have been used to calibrate ion implanters [6] and Fundamental Parameter measurements in XRF [7] (with RBS), and reference materials for industrial process monitoring by XRF [8] (with EBS). We report accurate RBS with a very robust Uncertainty Budget. 1 K.J.Kim et al., Thickness Measurement of nm HfO2 Films (CCQM-P190), Submitted to Metrologia Supplement. 2 M.P.Seah et al., Critical review of the current status of thickness measurements for ultrathin SiO2 on Si Part V. Results of a CCQM pilot study, Surface & Interface Analysis 36 (2004) 1269-1303 3 MEIS: medium energy ion scattering; XRR: X-ray reflectometry; XPS: X-ray photoelectron spectroscopy; XTEM: cross sectional transmission electron microscopy; SE: spectroscopic ellipsometry; RBS: Rutherford backscattering spectrometry; EBS: elastic (non-Rutherford) backscattering spectrometry; XRF: X-ray fluorescence 4 C.Jeynes, RBS as a new primary direct reference method for measuring quantity of material, Nuclear Instruments and Methods in Physics Research B, 406 (2017) 30-31 5 C.Jeynes, N.P.Barradas, E.Szilágyi, Accurate determination of Quantity of Material in thin films by Rutherford backscattering spectrometry, Analytical Chemistry 84 (2012) 6061-6069 6 J.L.Colaux, C.Jeynes, K.C.Heasman, R.M.Gwilliam, Certified ion implantation fluence by high accuracy RBS, Analyst, 140 (2015) 3251-3261 7 R. Unterumsberger, P. Hönicke, J.L. Colaux, C. Jeynes, M. Wansleben, M. Müller, B. Beckhoff, Accurate experimental determination of gallium K- and L3-shell XRF fundamental parameters, Journal of Analytical Atomic Spectrometry, 33 (2018) 1003-1013 8 C.Jeynes, E.Nolot, C.Costa, C. Sabbione, W. Pessoa, F. Pierre, A. Roule, G.Navarro, M.Mantler, Quantifying nitrogen in GeSbTe:N alloys, Journal of Analytical Atomic Spectrometry 35 (2020) 701-712

Resume : In this work, we present the results of a Round Robin test of different kinds of micro- and nanoscaled samples for Total Reflection X-Ray Fluorescence (TXRF) analysis for the first time. Therefore preselected, well-characterized samples including an internal standard were provided to the participants of the Round Robin test. Three different kinds of samples were to ensure very homogeneous mass depositions: First, manually produced ?L droplets, representing the most common sample preparation in TXRF. Second, nL droplets pipetted with a nL dispenser, having the potential of being ?L (total volume) samples distributed in an optimized way with respect to reproducibility and homogeneity. Third, multi-elemental sub-monolayers, coated over the entire sample surface, simulating surface contamination and thereby representing ideal samples for the method TXRF. One of the several elements coated as sub-monolayers was selected as internal standard and quantified with physically traceable XRF. The approach for an accurate and precise Round Robin activity was to separate the influence of the TXRF instrumental response and internal standard based quantification from any impact related to the sample preparation, in particular the spatial inhomogeneity revealed by different X-ray spectrometric techniques.

Resume : High-energy resolution X-ray emission spectroscopy becomes more advanced in terms of energy resolution and detection efficiency. In a nutshell, better sensitivity and discrimination capabilities are provided [1, 2, 3]. In order to move towards reliable investigations, calibrated instrumentation allows deconvoluting the spectra and differentiate between experimental and physical contributions. Theoretical techniques need to be developed and tested in order to support the interpretation of experimental data. Indeed, validated calculations allow analyzing the electronic structure of relevant materials for many scientific fields. Having a profound knowledge of the predictive power of the model used is crucial for this kind of considerations. In this work the electronic structure of titanium and titanium oxides is investigated using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). RIXS is in its simple description a combination of XAS and X-ray emission spectroscopy (XES). In order to obtain as complete a picture as possible, the K and L edges of the samples considered were investigated using either energy-dispersive detectors (XAS) or wavelength dispersive spectrometers (XES and RIXS). The deconvoluted results are compared to calculations of core-level spectroscopy based on ground-state (DFT) calculations [4] and the Bethe-Salpeter equation. Using the same set of input parameters of the electronic structure and atomic parameters throughout the calculations on the different datasets collected, the OCEAN code [5, 6] shows very good consistency with the experimental dataset of the well-known Ti and TiOx samples. The advantage of this experimental approach selected is that it allows identifying discrepancies when applying the OCEAN calculations to other elements or materials where the consistency is not provided yet. These insights can then be incorporated when analyzing new and/or complex application systems with unknown behavior, atomic or electronic structure. [1] Qiao et al., Rev. Sci. Inst. 88, 033106 (2017) [2] Chuang et al., Rev. Sci. Inst. 86, 013110 (2017) [3] Howak et al., Rev. Sci. Inst. 91(3), 033101 (2020) [4] https://quantum-espresso.org/ [5] K. Gilmore, J. Vinson, E. L. Shirley, D. Prendergast, C. D. Pemmaraju, J. J. Kas, F. D. Vila, J. J. Rehr, Comp. Phys. Comm. 197, 109 (2015) [6] J. Vinson, J. J. Rehr, J. J. Kas, and E. L. Shirley, Phys. Rev. B 83, 115106 (2011)

Resume : The measurement of acoustic vibrational modes is fundamental to the full comprehension of the mechanical properties of nano-objects, since they are connected to the intrinsic characteristics of the material, such as crystallinity, size, shape and elasticity. At the nanoscale, when localized plasmons couple to localized vibrations, the enhancement of inelastic light scattering signals from acoustic vibrational modes is expected. In this contribution, we investigate the coupling between plasmon and acoustic vibrations of assemblies of 100 nm Au nanocubes using low-frequency Raman spectroscopy. We show that changes in incident polarization affect the plasmon and thus modify the distribution of the electrical field inside the particles, therefore modifying the efficiency of the scattering by the acoustic vibrational modes. We also analyze the polarization of the scattered light for a given incident polarization as a way to correlate the behavior of the vibrational modes to the plasmon modes. We are able to observe a symmetric response of the vibrational modes related to the excited plasmon modes. The acoustic modes detected experimentally are identified with the help of numerical simulations representing vibrational and plasmon modes.

Resume : Silicon nanowires (SiNWs) array is a prospective surface with controlled physico-chemical properties that can be modified with functional materials depending on application tasks. One of the promising issues is related to the synergy between natural biomaterials and semiconductor structures. Dps (DNA-binded protein from starved cells) is a molecule with hollow spherical form which belongs to the bacterial ferritins group. These molecules shown an ability to form oxidized iron nanocluster core with spatial resolution limited by molecule dimension. The combination of Dps with SiNWs array may allow the formation of hybrid nanomaterials for nanoelectronics or spintronics. In this instance, Dps plays the role as an iron ions containing molecules with the size limited by few nanometers and identical form, structure and composition. The possibility of apo-Dps (iron free protein) filling in arrays of Si NWs is presented along with information on the composition and structure of the surface/bulk parts of the resulting structures. In frame of this study, the molecules ability to penetrate into the porous SiNWs array was investigated by applying a number of characterization techniques. The morphology studies of obtained surfaces in planar and cross-sectional views were performed by high-resolution scanning electron microscopy. The surface atomic and electronic structure and its chemical composition before and after Dps immobilization were studied by applying surface sensitive methods: synchrotron X-ray absorption near edge spectroscopy (XANES) for the estimation of the local surrounding of the given sort of atoms and lab X-ray photoelectron spectroscopy (XPS) for the chemical composition determination. The obtained results could play a key role in the future formation of composite nanostructures containing small iron nanoparticles. The work is supported under scholarship of the President of Russian Federation SP-189.2021.1 for young scientists.

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 10^20 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 : Last decades HfO2-based materials are considered mainly as alternative dielectrics to SiO2 due to their high dielectric constant, while optical and luminescent properties of such materials are addressed only in few reports. In this work, the impact of the doping with rare-earth (RE) elements (Er, Nd, Pr) on crystalline structure evolution and optical properties of HfO2 and HfSiOx films is reported. The films were grown on Si substrates by radio frequency magnetron sputtering in argon plasma and annealed at TA=800-1100?C for tA=15-60 min in nitrogen atmosphere. The transformation of film properties was studied by means of SEM, EDX, XRD, TEM and photoluminescence (PL) techniques. For HfO2 films doped with RE ions, the stabilization of tetragonal HfO2 phase in annealed films was observed contrary to monoclinic structure of pure HfO2 films. The main reason responsible for this phenomenon is formation of oxygen vacancies. For RE-doped HfSiOx films, a phase separation between SiOx and HfO2 occurs upon annealing. For Nd or Er-doped films, the presence of RE ions was detected in SiOx and HfO2 phases, while for Pr ions they were found in HfO2 phase only. This latter was transform into cubic one up to 1050°C, while formation of monoclinic HfO2 phase was detected after annealing at 1100°C. The shape of RE-related PL spectra followed the structure transformation. Narrow RE-related PL peaks were detected in the samples annealed at 1000-1100°C that confirms the location of RE ions in the phase with high crystal field. The peculiarities of PL spectra and the mechanism of phase separation for different films are discussed.

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 to 1.9 keV) and the hard X-ray branch (3 keV to 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] Y. Ménesguen and M.-C. Lépy, Nuclear Instruments and Methods in Physics Research Section A, Volume 1003, 165341 (2021)

Resume : Two-dimensional semiconducting transition metal dichalcogenides are promising materials for multidisciplinary applications including nano-photonics and bio-sensing, owing to their direct-bandgaps and high sensitivity to electronic doping. An important obstacle to commercial uptake is production of large area flakes with highly homogeneous spectral characteristics. Spectral inhomogeneities in freshly synthesised monolayers are indicators of poor performance in photonic and electronic applications, therefore making the study of spectral inhomogeneities especially important. Existing methods to reduce inhomogeneity are not scalable since they require direct physical manipulation, special substrates, and environmental conditions. Here we demonstrate a five-fold reduction in the spectral inhomogeneity in as-exfoliated monolayer WS2, resulting in enhanced photoluminescence emission (PL) and overall quality of WS2 flakes, by using a simple laser illumination process that works in ambient conditions. We demonstrate a statistical approach to evaluate spatial PL spectroscopy of exfoliated monolayer WS2 and quantify homogeneity. Analysis of the dynamic spectral statistics shows that the homogeneity enhancement is due to a spatially sensitive reduction of the trion spectral weighting, and that the spectral inhomogeneity is coupled to the electronic inhomogeneity of the flake.

Resume : International standards provide confidence to industry to create and adopt new materials. However, international standards can take years to develop, posing a challenge for companies that want to innovate quickly. Pre-normative research helps to accelerate development of standards and provide early access to best practice in materials development and characterisation. The Versailles Project on Advanced Materials and Standards (VAMAS) was created in 1982, following an Economic Summit of the G7, to promote world trade by innovation and adoption of advanced materials through international collaborations that provide the technical basis for harmonization of measurement methods, leading to best practice, reference materials and standards. The organization is composed of several technical working areas that define and deliver international scientific projects. This presentation will provide an overview of the technical areas of VAMAS (www.vamas.org). We will show the importance of global pre-normative work in providing confidence in the development and uptake of materials and show how interested academics and industry can participate in existing and future projects.

Resume : The characterization of airborne particulate matter using TXRF spectroscopy opens up many new opportunities to monitor the quality of the air we breathe. Exposure to fine particulate matter containing heavy metals such as arsenic, lead, cadmium or nickel appears to be directly related to cardiovascular diseases, although the pathophysiological mechanisms are not fully understood. Until now, the pollution of the air with heavy metals was examined by collecting particles by means of filters and subsequent ICP-MS analysis. TXRF spectroscopy, which requires significantly lower absolute sample quantities compared to ICP-MS, could provide the characterization of the heavy metal content at a higher temporal resolution due to the shorter sampling time required. For these reasons, we are working on the development of an impactor optimized for TXRF analysis, which separates airborne particulate matter into different size fractions. This impactor in combination with a TXRF spectrometer shall be designed as a fully automated unit for autonomous use over several days. We will present initial approaches to the design of the impactor, as well as first measurement results obtained in various locations in Berlin. This is intended to lay the foundation for instrument development with regard to heavy metals in atmospheric samples.

Resume : Structure and environmental response are crucial for the realisation of photonic materials with new functionalities. I will discuss how structure relates to optical response, and how smart materials can be used to create micro structures that are sensitive to their environment. In particular, I will look into the possibilities of creating 'intelligent' structures that respond and 'take decisions' based on changing environmental conditions.

Resume : Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors.[1,2] The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities. We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques.[3] The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ?1 and imaginary part ?2), electrical and electronic properties such as resistivity (?) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (?1) and imaginary part (?2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER. In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials. References [1] E. Ortel et al., Chemistry of Materials 2011, 23, 3201-3209. [2] M. Bernicke et al., ChemSusChem 2015, 8, 1908-1915. [3] R. Sachse et al., ACS Catalysis, 2020, 10, 14210-14223.

Resume : A large amount of research within organic biosensors is dominated by organic electrochemical transistors (OECTs) that use conducting polymers such as poly(3,4?ethylene dioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS). Despite the recent advances in OECT?based biosensors, the sensing is solely reliant on the amperometric detection of the bioanalytes. This is typically accompanied by large undesirable parasitic electrical signals from the electroactive components in the electrolyte. Herein, we present the use of in situ electrochemical Raman spectroscopy to understand subtle molecular structural changes of PEDOT:PSS associated with its doping level. For the first time, we demonstrate how the structural probe can be used on operational PEDOT:PSS OECTs for sensitive and selective metabolite sensing, while simultaneously performing amperometric detection of the analyte. We test the sensitivity by molecularly sensing a lowest glucose concentration of 0.02?mM in phosphate?buffered saline solution. When changing the electrolyte to cell culture media, the selectivity of in situ resonance Raman remains unaffected by other electroactive components in the electrolyte. The application of this molecular structural probe highlights the importance of developing biosensing probes that benefit from high sensitivity of the material's structural and electrical properties while being complimentary with the electronic methods of detection.

Resume : Nano-scale materials are important for a wide range of applications, including optical and electronic devices, whose functional performance properties are critically dependent on the nano-structure. However, detailed characterisation of structure-function relationships at the nano-scale presents a metrological challenge due to the small dimensions involved. In particular, the need for reliable, quantitative characterisation presents a barrier to successful commercialization of nanoelectronics devices. We consider the use of optical spectroscopy (confocal and near-field) as well as electrical modes of scanning probe microscopy (C-AFM) for characterisation of organic, inorganic, and hybrid nanomaterials. These techniques are sensitive to chemical and optoelectronic properties enabling direct access to structure-function relationships, but cannot be considered fully quantitative due to the lack reference samples and methods to enable traceability to the International System of Units (SI). Here we propose and demonstrate a suitable sample based on aligned semiconducting nanowires, which provide a linear feature roughly 10 nm wide with strong electrical and spectroscopic contrast that can be easily and uniquely identified. We present findings from a pre-normative VAMAS inter-laboratory study testing the suitability of these samples and the associated measurement protocol.

Resume : In situ optical configurations and evaluation models were developed for the ellipsometric monitoring of layer formation on metal surfaces. The surface processes can be monitored in a home-made environmental cell by a commercial ellipsometer in the wavelength range of 190-1690 nm at multiple angles of incidence during heat treatment in controlled atmosphere at elevated temperatures up 600 °C. The cell is based on a glass tube that supports focusing (down to a diameter of approximately 0.3 mm) and mapping along the axis of the tube. Processes during liquid flow can be monitored in a different cell construction that also supports focusing and mapping in a limited wavelength range and angles of incidence. The optical models require proper reference dielectric functions and advanced structural models that take into account the interface layers and vertical inhomogeneities. Since the optical configurations are capable of fast monitoring, complex kinetic models of the layer formation process were developed based on the large amount of time-dependent raw data and evaluated model parameters. The surface processes investigated using the new cells include the oxidation and Beraha type color etching of steel and zirconium surfaces.

Resume : With the development of imaging technologies, the detection of low-level metal contamination has become a compulsory research area to control the reliability and performance of devices. Early detection of unexpected metallic contaminants during device fabrication is key to avoid yield losses and secure the manufacturing line. Photoluminescence (PL) is a well-adapted technique for detecting metal contaminants thanks to its sensitivity to electrically active defects in the Si crystal [1]. However, it is well known that PL is also sensitive to surface states and related recombinations [2]. In this work, we study the sensitivity of PL to Cu, Ni, Fe and Pd contaminants at low concentration and we present a methodology based on the homogenization of surface recombination to separate their impact on PL from volume recombination. Samples were prepared from boron doped (100) oriented 300 mm CZ Si wafers with doping concentration at 1E15 cm-3. Wafers were contaminated by spin coating with Cu, Ni, Fe or Pd atoms brought in an ionic solution with doses from 1E10 to 1E13 cm-2. Those wafers were then annealed at 750°C during 5 hours under an O2 saturated atmosphere to diffuse the contaminants and form a thin SiO2 layer at the wafer surface. Full wafer PL image was acquired by scanning the samples with an 808 nm laser excitation and locally integrate the PL signal using a 2D array InGaAs camera. PL spectra were also locally extracted using a 638 nm laser excitation and a spectrometer equipped with an InGaAs photodetector. The penetration depth is respectively of few micrometers at 638 nm excitation and a dozen of micrometers for 808 nm, making the latter less sensitive to surface behavior. In parallel, surface potential was measured using a vibrating kelvin probe successively in dark environment and under high light excitation to extract surface barrier and its associated regime (accumulation, depletion, or inversion). Surface photovoltage measurements were performed to determine minority carrier diffusion length and measure more specifically iron contamination. First results show unexpected variations of PL with contamination dose that is believed to be caused by the effect of surface potential and associated regime. The method proposed consist of driving the surface regime to accumulation by negatively charges ions deposition [3]. In accumulation, surface recombination mechanisms are highly reduced and only volume recombination mechanisms are still active. The paper will present the difference obtained on PL behavior for Cu, Ni, Fe and Pd contaminants diffused in Si and how surface and volume recombination interfere. [1] V. Higgs, et al. Proc. SPIE 3895:21-371999. [2] T.H. Gfroerer. ?Photoluminescence in Analysis of Surfaces and Interfaces?. Encyclopedia of Analytical Chemistry (eds R.A. Meyers and G.E. McGuire) 2006. [3] T. Nassiet, et al. 31st ASMC conference 2020.

Resume : Roll-to-roll (R2R) nanoimbossing, where a rotating cylinder imparts a pattern on a moving foil, is an extremely fast way of mass-producing nanostructured surfaces. Most conventional nanoscale dimensional characterization techniques are too slow to keep up with R2R production speeds, and therefore unsuitable for in-line characterization and quality control. We present an optical, non-destructive, dimensional characterization method fast enough to keep up with R2R nanoimbossing. The method is based on a hyperspectral camera which provides both spatial (imaging) and spectral information from the moving foil. From the spectral information, the depths of embossed nanoscale line gratings can be determined via numerical scatterometric analysis. Thus it is possible to generate a spatial map of the grating depths, which can be considered a quality parameter for the embossing process. The grating depths were measured with an accuracy of a few nanometers, and reference height measurements with AFM confirmed the results. The method was tested in a production environment at foil speeds of 10 m/min, and higher speeds were shown to be possible.

Resume : Detection and extensive analysis of plastic micro- and nanomaterials (< 1.5 µm) are important to correctly assess toxicological healthy risks for humans. Here, we show the successive characterization of the same micro- and nanoplastic objects (standards, environmental, in tissues) using high-resolution complementary analytical techniques. Two precise relocalization approaches were demonstrated involving either a combined SEM-Raman instrument or independent instruments (SEM, HIM, micro-Raman, TERS) by means of a position encoder tag. In the first case, the stage with the sample is moved between the SEM and Raman positions within the same SEM chamber. In the second case, a so-called nanoGPS tag attached directly to the sample or sample holder is used to translate the sample coordinates corresponding to the regions of interest to the stage coordinates of different instruments regardless of the sample orientation. It was found that low-voltage SEM/HIM provide detailed surface imaging of single and agglomerated micro- and nanoplastics including size, texture, cracks, geometry, adhered pigments, biofilms, and other hazardous chemicals. Micro-Raman and TERS measurements on identical objects enabled usually their chemical identification, the latter down to nanoscale (~ 30 nm). These workflows are developed to account for statistically relevant monitoring of small-sized plastics towards reliable metrology and standardisation, being further supported by machine learning algorithms.

Resume : Phase change materials (PCM) based on Ge-Sb-Te alloys have interesting properties for a new generation of non-volatile memories. They exhibit rapid and reversible phase transformations between crystalline and amorphous states with very different electrical and optical properties. Thus, optical reflectivity and resistivity measurements during annealing are typically used to monitor the phase transition of PCM thin films, which are amorphous in their as-deposited state. In this study, the crystallization mechanisms of different PCM, GeTe and Ge2Sb2Te5 (GST) thin films are investigated using temperature-dependent in-situ spectroscopic ellipsometry. Previous studies have demonstrated the strong impact of surface oxidation in the crystallization process of PCM films. Nucleation can occur either at the surface followed by nucleation within the remaining amorphous volume (GST case) or growth from the surface layer (GeTe case) for surface oxidized samples, or directly into the volume at a significantly higher temperature by volume (or homogeneous) nucleation for non-oxidized samples (both GST and GeTe cases). The latter were obtained by a covering of their surface in situ after deposition with an oxidation protection layer made for instance of SiN, TaN or SiOx thin films. We will show how ellipsometry can be used to monitor these two crystallization processes and thus complement the reflectivity and resistivity measurements which have certain limitations.

Resume : Recent years have seen the blooming of many different 2D materials with exciting properties for many fields. Therefore, intense researches have also been done on how to transfer those materials from their growth substrates toward more workable surfaces. Among the methods developed, one use the effect of strain in a sublayer in order to delaminate, layer by layer, virtually any 2D material on a large scale. This process, called spalling transfer, was the object of several recent papers [1] et [2]. However, the mechanism underneath this method was barely investigated. In order to widen one of the bottleneck for large-scale use of 2D materials as well as to further understanding the out-of-plain strain propagation we reproduced this process. As a result, we successfully transferred 4 cm2 wide areas of Graphene from a sapphire substrate toward a SiO2 wafer using a strained Ni layer. To study this mechanism, we focused on Raman analysis, as it is an effective and in-line technique to survey the state of the Graphene. Therefore, here we propose a systematic Raman analysis of the Graphene during the spalling transfer in order to measure the impact on the Graphene brought by each step. We use the position of the 2D and G peaks along with interpretation proposed by Lee J. et al [3] to extract the strain and contamination from the Raman signal. We also took care to decorrelate the substrate?s effect from the Raman signal by doing a complementary wet transfer experiment. Then, the strain extracted from Raman analysis was corroborated by Synchrotron measurements and thermal dilatation calculus. On the other hand, the contamination was analyzed through TEM and XPS to understand its origin. This complete study should allow the fine-tuning of the transfer method to suit the need for strain or doping of the target application. [1] Shim, J. et al. Science 362, 665?670 (2018). [2] Saeedi, K. et al. Science 342, 830?833 (2013). [3] Lee, J. E. et al. Nature Communications 3, 1024 (2012).

Resume : Recent advances in two-dimensional materials and fabrication of heterostructures by stacking one monolayer layer on top of another has provided a wide range of possibilities to explore various fascinating phenomena. So far, the most studied heterostructure is the hexagonal boron nitride(h-BN)-graphene based heterojunction systems. While graphene is a semiconductor with zero bandgap, h-BN is an atomically flat insulator with a large band gap (~6 eV). h-BN has become a standard substrate for graphene-based devices due to its flat surface with no dangling bonds, and the lattice mismatch between h-BN and graphene which is only 1.8%. When two different regular patterns are superimposed, a new pattern emerges with larger periodicity, called a moiré pattern. These patterns can provide a wealth of information about the strain, electronic effects of lattice mismatch. The combination of atomically thin graphene and h-BN layer at a slightly rotated angle results in a well-defined moiré pattern and an associated super lattice structure, called Moiré Super Lattice (MSL) also changes their electronic properties. The periodicity of the MSL pattern depends on the twist angle between graphene and h-BN. Characterization of the moiré lattice and its periodicity is very critical in understanding the intriguing moiré physics. While traditional physical characterization techniques such as Transmission Electron Microscopy (TEM) have been used to image the MSL, these were done in non-ideal conditions and further require special sample preparation which might not be suitable for characterization in a device configuration. Also, the electron interactions can lead to unintentional and detrimental results. Scanning Probe Microscopy (SPM) techniques especially Scanning Tunneling Microscopy (STM) have also been used to study these MSL structures. Although STM yields atomic resolution images along with electrical characterization, the requirement of Ultra High Vacuum (UHV) conditions increases the turnaround time for the images. Other Atomic force microscopy (AFM) based techniques and their electrical derivatives have also been used by several groups to study the MSL structures. In this work, we report the use of scanning Microwave Impedance Microscopy (sMIM) under ambient conditions to obtain ultra-high resolution images of MSL?s formed between graphene and h-BN. sMIM is a cantilever based near-field electrical SPM technique in which microwave signals are sent through a specialized AFM probe with a shielded cantilever. As the AFM tip raster scans in close proximity with the sample surface, the microwave signals are transmitted to the sample and the reflected signals are collected by the same tip. The reflected microwave signals represent the local variations in the capacitance and resistance of the sample. In the ScanWave implementation of sMIM, microwaves of 3 GHz energy are delivered to the tip in a shielded cantilever and the reflected microwave signal is resolved by an RF mixer into the sMIM-C and sMIM-R channels which are related to permittivity and conductivity of the sample, respectively. Additionally, if the sample is AC biased, the system can measure the dC/dV and dR/dV response of the sample being imaged. sMIM can be used in ambient conditions to routinely image the periodicity of the MSL. As sMIM can provide high resolution (sub 2 nm) images of MSL, this can be used for routine inspection of the twist angle between the 2D materials with a very high throughput. Honeycomb structures of the MSL images with periodicity ranging from (14 nm to 5.5 nm) will be shown.

Resume : Two-dimensional semiconductors, specifically the broad class of transition metal dichalcogenides (TMD) attract significant attention of research community in recent years due to the wealth of interesting and potentially applicable phenomena observed in these materials. In order to control the performance of devices based on TMDs, it is important to characterize their properties at the scale relevant to the corresponding application, which in most cases today corresponds to a few tens of nanometers. Conventional far-field photoluminescence (PL) and Raman imaging provides highly averaged information with spectral congestion. In contrast, the TEPL and TERS methods (Tip-Enhanced Photoluminescence and Tip-Enhanced Raman Spectroscopy) performed with an AFM-Raman system, not limited by diffraction, provide substantial information related to nanoscale optical properties of 2D materials with resolution down to a few nanometers. In this talk, we report on the application of scanning probe microscopy (SPM) cross-correlated with Tip-enhanced optical spectroscopies (TEOS) such as TERS (tip-enhanced Raman spectroscopy) and TEPL (tip-enhanced photoluminescence). The techniques are used to image various TMD (MoS2, WS2, MoSe2, WSe2) alloys and heterostructures revealing detailed nanoscale features and unexpected heterogeneities. We will demonstrate the power and importance of the cross-correlation of nanoscale hyperspectal imaging with data from other scanning-probe techniques such as topography, surface potential, conductivity and photocurrent. These variations in the nanoscale optical and chemical properties correlating with the structural information obtained with SPM can provide a better understanding of the 2D TMD materials for the future development of highly efficient, flexible, lightweight optoelectronic devices.

Resume : Space-resolved measurements of electrical properties of nano structured materials play a crucial role for the realization of homogeneous transparent conductive electrodes based on thin films, 2D materials or nanowire networks. These nano structured materials are typically electrically characterised by means of four-point probe techniques, both in-line and van der Pauw configurations. These techniques, though relatively easy to implement and well established for a wide range of materials, present both i) a strong dependence of the results on the sample uniformity, and ii) limited capability to obtain space-resolved information about the conductivity of the sample. At the conference we will highlight Electrical Resistance Tomography (ERT) as a non-destructive technique for space-resolved measurements of electrical conductivity of nano structured materials [1-3]. This technique allows, by measuring a set of four-terminal resistance at several electrodes on the sample boundaries, to reconstruct a conductivity map through the solution of an inverse problem. Examples of the application of the technique will be reported at the conference about the characterisation of transparent conductive oxide films, chemical vapour deposited graphene layers on large area substrates, and we will show first results of the application of ERT to nanowire networks. References [1] G. Milano et al., Mapping Time-Dependent Conductivity of Metallic Nanowire Networks by Electrical Resistance Tomography toward Transparent Conductive Materials, ACS Appl. Nano Mater., in press, 2020. [2] A. Cultrera et al., Mapping the conductivity of graphene with Electrical Resistance Tomography, Sci. Rep., vol. 9, no. 1, 2019. [3] A. Cultrera and L. Callegaro, IEEE Trans. Instrum. Meas., vol. 65, no. 9, 2016.

Resume : A fundamental step to attain the goals of CHALLENGES project is represented by the realization of plasmonic tips fully compatible with a CMOS production environment, which requires in particular the replacement of noble metals like Ag with materials not poisonous in a clean room line. Thus suitable materials must be selected and used to realize innovative probes, which can take advantage also from the use of advanced and not standard shapes and geometries of the tips. In this work, the current status of the researches of CHALLENGES team focused on this topic is presented. In particular, the current status of research is reviewed and the most recent theoretical and experimental results are presented. Both analytical models and numerical simulations are implemented to investigate the properties of the most promising plasmonic materials for a tip. This project has received funding from the European Union?s Horizon 2020 research and innovation programme under grant agreement No 861857.

Resume : The evolution of nanoscience and nanotechnology has empowered several industrial sectors with new approaches to design and control material properties up to the molecular level and the atomic scale. Therefore, industries producing innovative nano-enabled materials and devices are facing the urgent need of nanoscale real-time characterization methods and tools to be introduced within the production lines to ensure reliability of the fabrication process. The European H2020 project CHALLENGES (full title ?real-time nano-characterization related technologies?) addresses this need by developing innovative Non-Destructive Techniques (NDTs) for reliable inline multiscale measurements down to the nanoscale, which are fully compatible with different factory environments. The final goal is to develop nanoscale metrological NDTs, using plasmonic enhanced Raman, infrared, and photoluminescence signals, based on Scanning Probe Microscopy platforms, for measurements of doping, annealing, metal contamination, dangling bonds and strain directly within the production lines with real-time capabilities. In particular, the CHALLENGES project focuses on demonstrating the usefulness of these new NDTs in three different nanomaterial production environments, namely in semiconductor industry (for optical sensors and strain-channel transistors), in photovoltaics (for ultra-thin silicon wafers and silicon-based solar cells) and for devices based on 2D materials (graphene layers and transition metal dichalcogenide [TMD] monolayers). In this contribution, we focus on the nano-characterization challenges that need to be tackled and why in-line nano-characterization will be very useful for the various classes of materials and devices described above. In several other accompanying symposium contributions, more details will be given about the proposed in-line nano-characterization solutions themselves. We will provide for each of the material/device classes a detailed overview of all to be measured physical and chemical quantities together with the required measurement characteristics such as measurement range, required accuracy and spatial resolution, required timescale of the measurement, etc. We will clearly explain the main challenges for each of the different devices/materials with respect to nano-characterization. As an example, we take in this abstract the strain channel transistors whose performances are based on the increase of carrier mobility induced by the controlled introduction of mechanical strains in the transistor channel (sSi or sSiGe for n or p transistor respectively). Monitoring the relaxation of the patterned gate is required to control transistor/device performances. As the gate is typically smaller than 20 nm, metrology of the strain at the gate scale is of first importance.

Resume : A cost-efficient production of reliable, innovative materials and devices like advanced electronics products requires nanoscale real-time in-line control during manufacturing. State-of-the-art techniques capable to map physical observables at the nanoscale compatible with in-line operations, like Raman, InfraRed (IR), Photoluminescence (PL) spectroscopy, do not have typically enough resolution for the detailed characterization of nano-scaled devices. Signal amplification by localized plasmon resonance at a sharp tip can give the opportunity of improving both the spatial resolution and the signal/noise ratio. The European H2020 CHALLENGES project main objective is to develop multipurpose nano-optical techniques and metrological protocols for real-time characterization, using plasmonic enhanced Raman, IR and PL signals, capable to enable an increase of speed, sensitivity, spectral range with full cleanroom compatibility within different production environments, to improve devices performance, quality and reliability. From the methodological point of view, one of the key points of the proposed approach relies on the validation activities carried out by the state-of-the-art conventional techniques, with the main objective of demonstrating that the measurements of the characteristic physical quantities achieved with the newly developed systems are completely coherent with what can be obtained with the techniques conventionally used to perform nano-characterization activities.

Resume : Semiconductor industries producing innovative materials and devices face the urgent need for real-time characterization methods. To ensure the reliability of the fabrication process and in R&D, standardized metrological evaluation of procedures and data treatment is crucial to be introduced within the production line [1]. For example, this applies to the development of metrological measurements and characterization of stress and strain at the micro and nanoscale under industrially relevant conditions. Micro-Raman spectroscopy is one of the established spectroscopic methods for measuring local mechanical stress and strain distribution. Probing the lateral crystal morphology and strain in materials (e.g., 2D materials like graphene and MoS2, SiGe for FET applications, GaN pillars for LEDs) is non-destructive. It can be carried out without laborious sample preparation [2-5]. Furthermore, the mapping of strain in semiconductor epilayers and large area devices is easily achieved with a lateral resolution better than 500 nm. Here, we introduce the state of the art of strain evaluation with Raman spectroscopy in 2D materials (e.g., graphene) and selected semiconductor samples (e.g., SiGe). Based on this, we demonstrate how the implementation of metrologically traceable measurements of lateral strain will be achieved in the H2020 project ?Real-time nano-characterization related technologies ? CHALLENGES? [6]. Complementarily to the Raman characterizations stress and strain values of selected CHALLENGES samples are to be determined by means of X-ray Extended Absorption Fine Structure (EXAFS) techniques using tunable synchrotron radiation as incident radiation and element-specific x-ray fluorescence radiation in the detection channel [7]. While XRD reveals lattice parameters of crystalline materials only, the energy-dependent EXAFS absorption modulations of a nano- or microscaled layer can be transferred into a distance distribution of nearest-neighbor atoms with respect to the element of interest. References [1] N. G. Orji et al., Nature Electronics 1, 532-547 (2018) [2] S. Wundrack et al., Phys. Rev B 99, 045443 (2019) [3] Z. Liu et al., Nature Communications 5, 5246 (2014) [4] S. Nakashima et al., J. Appl. Phys 99, 053512 (2006) [5] F. Demangeot et al., J. Appl. Phys 91, 2866 (2002) [6] https://www.challenges2020.eu [7] F.Reinhardt et al., Anal. Chem. 81, 1770 (2009)

Resume : We present here magnetic and field emission (FE) properties of FeCO and Ni nanoparticles (NPs) embedded in thin silica matrix. FE measurements were carried out in an indigenously developed high vacuum diode set up. The results obtained in this study are (i) elongation of metal NPs due to swift heavy ion irradiation, (ii) appreciable increase in FE current density with high mechanical durability of shape engineered NPS: a promising planar emitter for future flat-displays (iii) Magnetic anisotropy and exchange bias effect in shape engineered NPs. The results are understood from a combined experimental results, electronic structure first-principles based calculations study.

Resume : Scanning Thermal Microscopy is a widely recognized technique for thermal conductivity measurements of bulk and nanostructured materials. Wollaston probes are presently used in contact or noncontact mode for thermal conductivity measurement. They can be reliably fabricated in the laboratory and offer an appropriate spatial resolution from few microns to hundreds of nanometers. A study is reported herewith on the errors that can affect the average temperature rise and related probe thermal resistance with direct impact on thermal conductivity evaluation, as a consequence of a contact point asymmetry. The new theoretical models proposed and its results can be used or adapted to any kind and size of hot probe. The study is based on the fin heat conduction equation applied on three regions of the probe: left, middle and right, in respect to the contact point. The thermal conductivity calculation for a thin film on substrate is simulated and the errors that raise from using an asymmetric contact point are inferred for the three values of the asymmetry. They are next compared to simulations obtained using a simplified model of heat transfer inside the probe and from probe to sample. The accuracy of the two models is comparatively analyzed in order to select the optimum one. The error in the simulated average temperature of the probe is investigated as a function of four probe diameters and lengths in order to assess the scaling influence. A general analysis of the errors affecting the thermal conductivity measurement is presented as a function of the experimental data spread out in the probe average temperature measurement. This analysis can serve as an eventual evaluation criterion of experimental precision of the method and improvement possibilities.

Resume : Transient heat transport is governed by the electrons and the phonons in many nanoscale applications. A new observed thermal behavior in the alloys called superdiffusive regime based on the Levy dynamics[1] is present at specific space and time scales. It is an intermediate regime between the ballistic and diffusive regimes, in which usually govern the phonon transport. The frequency range of this regime is accessible through the high-resolution 1 THz spectral bandwidth, obtained by the femtosecond pump-probe Heterodyne[2] experiment patented by LOMA. This broad spectral bandwidth makes this technic a phononic spectrometer. In this context, to measure the phonon spectrum, a transducer of a few tens of nanometers is deposited on top of the layer of interest. This transducer should be a metallic film with high thermal conductivity chosen to maximize the absorption of the laser in the sample and to make a heat reservoir as well. Moreover, it transfers its energy to the layers underneath and permits them to probe their thermal behavior optically. This transducer hence plays an essential role in the description of the sample spectral response. This part of our work will consist of characterizing the thermal behavior of the Au and Al transducer with a Two Temperature Model. The method presented will make it possible to choose the most efficient transducer in order to obtain a broad spectral bandwidth, which will enable an optimized analysis of the superdiffusive regime in the layers underneath. References: 1. B. VERMEERSCH, J. CARRETE, N. MINGO, AND A. SHAKOURI, ?Superdiffusive Heat Conduction in Semiconductor Alloys. I. Theoretical Foundations,? Phys. Rev. B, vol. 91, 2015. 2. S. DILHAIRE, G. PERNOT, G. CALBRIS, J. M. RAMPNOUX, AND S. GRAUBY, ?Heterodyne Picosecond Thermoreflectance Applied to Nanoscale Thermal Metrology,? J. Appl. Phys., vol. 110, 2011.

Resume : Within the EMPIR project ADVENT, in which the metrology for advanced energy-saving technology in next-generation electronics applications is further developed, the Physikalisch Technische Bundesanstalt (PTB), Germany´s national metrology institute, contributes to the characterisation of novel ferro- or piezoelectric materials by using traceable X-ray methodologies for the in-situ characterisation of advanced materials. Therefore extended X-ray absorption fine structure (EXAFS), which allows determining the atomic coordination within the investigated material under in-situ conditions, is applied towards operando measurements of the response of PZT-films to alternating electric fields applied at a frequency in the megahertz range. We will present the current progress towards time-resolved traceable atomic coordination measurements of piezoelectric materials proposed for the next generation of ultra-low power energy-efficient devices. The provision of analytical information on real materials within operational environments allows, in conjunction with complementary analytical techniques, linking the intrinsic physical phenomenon to the materials? macroscopic functional and structural properties.

Resume : Atomic layer deposited aluminium oxide is the material of choice for the surface passivation of silicon, especially in the case of nanotextured light absorbing surfaces. The excellent passivation performance of aluminium oxide is based on its good interfacial properties with silicon as well as the high negative charge of the passivating film. Stable surface passivation performance is vital for commercial photovoltaic devices making use of the nanostructured silicon surfaces, such as sensitive photodetectors and high-efficiency solar cells. Recently, we showed that damp heat exposure and light soaking can cause significant degradation of aluminium oxide surface passivation, but the exact degradation mechanisms require further studies. In this work, we investigate how damp heat exposure and light soaking affect aluminium oxide passivation films using Photoelectron Emission Spectroscopy (PES). Our results showed no differences between the undegraded and degraded samples regarding the positions or the area of the peaks corresponding to Al2p, Si2p or Al2s orbitals. However, significant differences were observed in the areas of the peaks corresponding to O1s orbitals close to 533 eV. These findings indicate that damp heat and light soaking conditions primarily affect the bonding of oxygen in the aluminium oxide films.

Resume : Rational nanoparticle design is one of the main goals of materials science, but it can only be achieved via a thorough understanding of the growth process and of the respective roles of the molecular species involved. We demonstrate that a combination of complementary techniques can yield novel information with respect to their individual contributions. We monitored the growth of long aspect ratio silver rods from gold pentatwinned seeds by three in situ techniques (small-angle x-ray scattering, optical absorbance spectroscopy and liquid-cell transmission electron microscopy). Exploiting the difference in reaction speed between the bulk synthesis and the nanoparticle formation in the TEM cell, we show that the anisotropic growth is thermodynamically controlled (rather than kinetically) and that ascorbic acid, widely used for its mild reductive properties plays a shape-directing role, by stabilizing the {100} facets of the silver cubic lattice, in synergy with the halide ions. This approach can easily be applied to a wide variety of synthesis strategies.

Resume : We study the assembly kinetics of surfactant-stabilized gold nanoparticles in the presence of sulfate ions. The reaction proceeds in two steps: very rapid (a few minutes) formation of amorphous aggregates, followed by slow reordering (over several hours). The latter process is the only one detectable via absorbance spectroscopy and results in the formation of intimate contacts between the objects, with interparticle distances below the thickness of a surfactant bilayer. The rate-limiting step of the reaction could be related to surfactant expulsion from the initial aggregates, which allows the particles to come in close contact and form chains. There are marked differences in reaction yield and rate constant between spheres, rods and bipyramids, highlighting the role of surface curvature in contact formation. Once formed, the assemblies are very sturdy and stable under centrifugation and dialysis. The contact interaction is strong and highly directional, as shown by liquid-cell transmission electron microscopy.

Resume : In the past decades, intrinsically conducting polymers have been an important research topic in the field of new and non-inorganic electronic devices as alternative to silicon-based technologies. Moreover, the nanostructure engineering of conducting polymers has been widely studied for both fundamental research and potential applications. In this context, there has been a continuous demand for precise characterization tools, able to determine physical and chemical properties at nanoscale levels. These techniques must accurately measure, predict, and elucidate underlying connections among structure, properties, and dynamics. Following this idea, in this work, we present the use of atomic force microscopy (AFM) techniques for studying local mechanical properties of conductive polymer nanostructures. The nanostructures were fabricated using PEDOT:PSS, one of the most used and commercially available conducting polymer materials. We prepared conducting polymer nanospheres using a one-step surfactant-free preparation method [1]. Also, we prepared PEDOT:PSS nanostructured thin films by solvent vapor annealing. The AFM-based approach allowed to determine the structural, mechanical and electrical properties of the nanostructures simultaneously. In particular, nanomechanical properties were determined by combining Peak Force Quantitative Nanomechanical Mapping (PF-QNM) experiments with Force Spectroscopy measurements. These studies revealed the presence of distinct mechanical phases and allowed the quantification of the nanostructures? local mechanical properties. To probe the functionality of the samples, electrical conductivity was measured by AFM. We were able to map preferentially conductive areas of PEDOT:PSS nanostructures, and to quantify the conductivity of single polymer structures. Our set of results highlight the use of AFM as a fast and precise technique, able to determine laterally-resolved properties of polymer with applications in energy. Moreover, our results serve as starting point toward providing further deep knowledge about the molecular origin of macroscopic properties of these systems. Also, the presented nanoscale studies will contribute providing know-how able to solve current problems in the application of polymer in energy systems as low efficiency, low power density, overheating, inadequate mechanical properties, and long-term material stability. [1] Matteo Sanviti, Angel Alegria, Daniel E. Martínez-Tong. Fabrication and nanoscale properties of conducting polymer nanospheres based on PEDOT:PSS. In preparation.

Resume : Scanning Near-field Optical Microscope (SNOM) is a tool for a non-destructive characterization of samples with very high lateral resolution. The resolution is basically given by an optical fibre aperture and can go well below 100 nm. Hence, the limitation given by the diffraction limit can be overcome. We have modified a commercial SNOM for spectroscopic measurements to provide quantitative results instead of only local contrast. We have combined results from spectroscopic SNOM (sp-SNOM) with results from another tool for an optical characterization, namely a spectroscopic imaging reflectometer, to obtain quantitative results on millimetre-scale ranges with locally enhanced lateral resolution. Reflectance spectra acquired by the sp-SNOM were validated by the imaging reflectometer on overlapping areas and supported by Finite Difference in Time Domain calculations. The optical characterization of different silicon dioxide thin films deposited on silicon substrates was further supported by topography measurements using Atomic Force Microscope.

Resume : The GRACE project [1] aimed to an accurate approach to the electrical characterisation of graphene, through the development and comparison of both contact and non-contact methods, with traceability to the electrical SI units. The GRACE consortium also collaborated with standardization bodies, i.e. International Electrotechnical Commission (IEC), to develop new technical specifications that will enable the industry to harmonize the quality of the graphene-based future electronic products. Within the GRACE project we developed validated electrical characterisation protocols specifically for graphene; the investigated methods were both contact and non-contact techniques. Chemical vapour deposited graphene samples were produced and circulated among the partners during the project in order to test, on each sample, more than one of the above-cited characterisation methods and compare the measurements outcome. The results of this inter comparison allowed to understand how to meaningfully implement different methods, and the gained experience has now been collected in two Good Practice Guides [2], that will be presented at this Conference. References [1] EMPIR 16NRM01 GRACE (2017-2020) --- Developing electrical characterisation methods for future graphene electronics. [2] Online: http://empir.npl.co.uk/grace

Resume : The COST Action CA 18130 "European Network for Chemical Elemental Analysis by Total Reflection X-Ray Fluorescence" acronym ENFORCE-TXRF (https://enforcetxrf.eu), aims to coordinate research and building capacity in the field of elemental analysis by total reflection X-ray fluorescence spectroscopy (TXRF) in order to develop and assess new tools, protocols, methodologies, and instrumentation for screening and accurate determination of elemental presences and concentrations. The elements targeted are ranging from toxic elements to health, to metal contamination on nanostructured materials or Si wafers. Such analysis may have tremendous repercussions in quality control practices, or in establishing regulatory policy. This Action constitutes an infrastructure for scientific exchange and collaboration to enhance technical standards, and to advance measurement science. This fosters new research activities and allows to combine the various partners? related expertise in chemistry, physics, life science and engineering. This network will provide the tools to maximize European competitiveness in forming talented scientists, supporting new capabilities that improve research innovation, productivity, standardisation, and quality. ENFORCE-TXRF is opened to all interested in contributing in TXRF field of research, worldwide (enforcetxrf@gmail.com). Acknowledgment: Abstract based upon work from COST Action CA18130 supported by COST (European Cooperation in Science and Technology) www.cost.eu

Resume : Exposure to nanomaterials is continuously increasing in occupational and consumer settings alike, as the use of nanomaterials is becoming more common in research and industry, and commercial products containing nanoforms are being progressively introduced into the market. Research work in the field of nanosafety has demonstrated that some species of nanomaterials may display high health risk potential, determined by a number of factors including structure, chemical properties and processing methods used. Evaluation of the health and environmental hazards of nanomaterials, as well as identification of the appropriate strategies to mitigate risks is essential for the benefits of nanotechnology to be maximally exploited. While significant nanosafety research progress has been achieved in recent years, given the newness of the nanotechnology field, there still exist significant barriers in terms of information gaps that disenable full quantitative evaluation of nanomaterial risk. This has led a great volume of nanosafety research to focus on the qualitative or semi-quantitative methodology of control banding. This is an approach in which control strategies (such as Local Exhaust Ventilation or containment) are applied to processes according to a risk band classification, determined through analysis of material and process data. However, it is unclear if conventional control banding approaches can accurately depict risks encountered in nanomaterial processes. The nature of these processes is such that high temporal and spatial variation is expected for potential emissions, while exposure may manifest through widely different pathways and in different magnitudes for each process stage (e.g. precursor weighing, main production, post-processing). Increased flexibility may be required in order to more concisely classify processes in terms of risks. This work describes the development of an expanded control banding methodology, adapted to the needs of nanosafety evaluations. The risk characterization process is supported by material information gathering, conducted exposure measurements as well as data produced from process specific exposure simulations. A three-dimensional approach is utilized, employing discrete hazard, probability and exposure analyses, in order to evaluate each constituent of risk. The objectives of our method is to aid in the optimization of nanomaterial processes and the layout of workspaces, evaluate the effectiveness of control measures, and provide insight on developing Safe-by-Design processes. This information can be valuable for decision making towards efficient risk management of nanomaterial processes.

Resume : Modern complex research dedicated to fabrication and characterisation of novel materials requires a broad list of costly equipment which is in many cases not available at the same research unit, especially true for academic institutions or scientific centres with poor budget. In such conditions, researchers either are looking for collaboration to perform required experiments, or waiting/applying for financial support, or even just giving up with that potentially promising research idea. If such collaboration contacts are existed, very often they are placed far away in other countries or continents, which means a time and money consuming procedure to carry out a visit and research or even just send samples for analysis. Young scientists and early career investigators are even more sensitive for such problems since their own scientific network may be not well grown yet. The development of everywhere reaching online database of material research facilities will help in described situations as well as in many other cases. Research units of any type may also benefit from placing equipment in the database as a tool to increase their visibility and to find new collaborations and projects. First studies of opinions and expectations from the database have been performed among material science researchers and research units’ management. Basic principles and functionality will be presented.

Resume : Molecular movement through their pore network is one of the most important characteristics of porous materials, such as zeolites. It dictates the overall performance of these materials for adsorption and separation as well as catalysis. The influence of local pore structure on molecular movement is particularly relevant for zeolites with the MFI framework topology, constituting a network of perpendicular sinusoidal and straight channels with distinct geometry and width. To date, mobility in single channel orientations has mainly been studied with pulsed field gradient nuclear magnetic resonance imaging, which provides only limited understanding of molecular motion because of ensemble-averaging [1]. In this work, we use single-molecule localization microscopy to directly visualize and study the diffusivity of molecules within each channel type of ZSM-5 zeolite films. We also follow the effect of the introduction of secondary pores on the molecular mobility. Building on previous work in our group, we have developed a unique approach of single-molecule tracking and trajectory classification [2] in uniformly oriented ZSM-5 zeolite thin films [3]. This allows us to quantify the mobility of molecules in both the sinusoidal and straight channels as well as the effect of heterogeneities on the single-molecule level. Subtle differences in zeolite channel geometry dramatically alter diffusivity of the molecules, illustrated by up to an order of magnitude faster diffusion within the straight zeolite pores than in their more constrained sinusoidal counterparts. Using our classification-based single-molecule approach, we find that this difference is due to a higher number of immobile molecules as well as a lower mobility of mobile molecules in the sinusoidal channels. Thus, the more tortuous pore geometry of the sinusoidal channels results in dramatically slower local diffusion. We further investigate hierarchical zeolites and find that the introduction of secondary pore networks via etching dramatically increases the average mobility of molecules in sinusoidal channels. More precisely, it both reduces the number of immobile molecules and doubles the diffusivity of mobile molecules. In contrast, the diffusivity of mobile molecules in the straight channels is unaffected. These results suggest preferential formation of interconnected secondary pore networks along the sinusoidal channels, which is line with previous work [4]. Altogether, with single-molecule imaging on uniformly-oriented zeolite thin films as a well-designed model platform, we demonstrate how the local pore structure affects mass transport through an anisotropic zeolite material. 1. Zeng, S., et al. ChemCatChem 12, 463 (2019). 2. Hendriks, F. C., Meirer, F., et al. J. Am. Chem. Soc. 139, 13632 (2017). 3. Fu, D., et al. Angew. Chem. Int. Ed. 56, 11217 (2017). 4. Qin, Z., et al. Angew. Chem. Int. Ed. 55, 15049 (2016).

Resume : Many exciting applications of nanophononics occur beyond thermal equilibrium [1], yet the direct detection of non-thermal acoustic phonons with frequency- and momentum-resolution remains challenging. In this talk, we will present pumped-BLS [2], a technique for ultrafast photoexcitation and frequency-domain detection of non-thermal acoustic phonons. Using this method, we achieved a hundred-fold enhancement of BLS spectra of 260 nm thick Si membranes than at thermal equilibrium due to photoexcited non-thermal gigahertz phonons. Furthermore, we observed such spectral features as Stokes / anti-Stokes asymmetry due to asymmetric non-thermal phonon propagation and strongly asymmetric Fano resonances due to interaction with the continuum of electron-hole pair excitations. This project received funding from NCN (UMO-2018/31/D/ST3/03882), ERC (grant no. 694977), and FNP (POIR.04.04.00-00-5D1B/18). TV acknowledges funding from the European Union's Horizon 2020 research and innovation programme. [1] M. Sledzinska, et al. Adv. Funct. Mater. vol. 30, no. 8, 2020. [2] Th. Vasileiadis et al. Science Advances Vol. 6, no. 51, eabd4540, 2020.

Resume : Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are two of the most used, complementary techniques for surface analysis at the nanoscale. Thus, combining them by integrating a compact AFM into SEM brings novel possibilities for true correlative imaging and advanced multi-modal sample characterization that would be often unfeasible using each imaging modality separately. LiteScope is produced by the NenoVision company and represents a compact AFM, which is designed to be integrated into a large variety of SEMs in a plug-and-play manner. In general, the strength of the AFM-in-SEM hybrid system lies in combining the AFM modes (3D topography, electrical, mechanical and magnetic measurements) with SEM capabilities (fast imaging with wide resolution range, chemical analysis, surface modification using FIB/GIS etc.). Further benefits include precise AFM tip navigation by SEM to the region of interest, roughness evaluation and in-situ conditions, which is essential for sensitive samples and minimizes sample handling. Uniquely, LiteScope design enables simultaneous acquisition and correlation of AFM and SEM data by NenoVision?s proprietary technique called Correlative Probe and Electron Microscopy (CPEM). CPEM functionates in a way that the electron beam and AFM tip keep a constant offset and remain static during the image acquisition. The scanning movement is conducted by a piezo scanner that carries the sample. This ensures simultaneous SEM and AFM data collection in the same coordinate system and with identical pixel size. The resulting 3D CPEM view can combine multiple channels, both from AFM and SEM, enabling thorough sample analysis and clear data interpretation for specific applications. In conclusion, the AFM-in-SEM strategy benefits from the complementarity of both techniques alongside significant savings both in time and resources. Also, it opens completely new possibilities for advanced data correlation and measurements in variety of industrial and research applications, such as semiconductors, material-, biological- and earth-sciences.

Resume : Dislocations have been considered to be an efficient source for scattering midfrequency phonons, contributing to the enhancement of thermoelectric performance. The structure of dislocations can be resolved by electron microscopy whereas their chemical composition and decoration state are scarcely known. Here, we correlate transmission Kikuchi diffraction and (scanning) transmission electron microscopy in conjunction with atom probe tomography to investigate the local structure and chemical composition of dislocations in a thermoelectric Ag-doped PbTe compound. Our investigations indicate that Ag atoms segregate to dislocations with a 10-fold excess of Ag compared with its average concentration in the matrix. Yet the Ag concentration along the dislocation line is not constant but fluctuates from ?0.8 to ?10 atom % with a period of about 5 nm. Thermal conductivity is evaluated applying laser flash analysis, and is correlated with theoretical calculations based on the Debye?Callaway model, demonstrating that these Ag-decorated dislocations yield stronger phonon scatterings. These findings reduce the knowledge gap regarding the composition of dislocations needed for theoretical calculations of phonon scattering and pave the way for extending the concept of defect engineering to thermoelectric materials.

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 poster 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.

Resume : Aluminium gallium nitride/gallium nitride (AlGaN/GaN) high electron mobility transistor (HEMT) structures have been widely used in high power and high-frequency applications up to the THz frequency range. In order to reduce the density of threading dislocations and to provide an electrically isolating layer the standard HEMT structures usually contain thick acceptor doped GaN buffer. Recently developed "buffer-free" AlGaN/GaN heterostructures on SiC substrate without the usage of thick GaN allow to avoid buffer-associated trapping effects and improve thermal management. In this work, the structural and morphological properties of these heterostructure layers will be analyzed with high precision. The results of structural analysis employing XRD, TEM methods, and morphology methods such as AFM will be discussed. For example, AFM measurements revealed the characteristic RMS roughness values to be as small as Sq=0.56 nm over the scan area of 1.5 microns squared. Moreover, recent study on the electrical and noise properties of Schottky barrier diodes and HEMTs, developed of this "buffer-free" AlGaN/GaN material, has revealed the improved thermal stability, low trap density, and suitability for high-frequency and high-power applications in correlation with good structural and morphological characteristics of this novel material [Micromachines vol.11 p.1131 (2020)].

Resume : Titanium dioxide nanotubes were synthesized by anodic oxidation of titanium foil using ammonium fluoride and an ethylene glycol-based electrolyte. The nanostructures were then thermally annealed at various temperatures in different atmospheres and subsequently characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The results indicate that the crystal structure and crystallinity depend strongly on both the annealing temperature and annealing atmosphere. Anatase phase TiO2 was observed to vanish rapidly with increasing temperature in an oxygen environment , while it remained more stable and predominant than the rutile phase at elevated annealing temperatures in vacuum. XRD patterns revealed the dominance of the phase and small amounts of the rutile phase upon annealing at 600oC in air or in nitrogen flow (300 cc/min). In a similar oxygen flow, the rutile phase was observed already after annealing at 500oC and the intensity of the XRD peaks of the rutile phase increased rapidly with temperature. Upon annealing in vacuum, only the anatase phase was observed up to 600oC, while the rutile phase was obtained from 700oC. However, the anatase phase remained dominant up to 900oC. This suggests that the rutile phase is stable above 600o C in vacuum but does not evolve significantly with increasing temperature. SEM showed that the openings of the tubes tended to reduce in size with increased annealing temperature and less cracking was observed for tubes annealed in vacuum. Room temperature photoluminescence showed relatively low intensity spectra, indicating poor radiative recombination and a dependence on the crystallite size in the nanotube walls.

Resume : Composition of diatom rocks from the deposit of Kazakhstan (Aktobe region) was studied by experimental methods: silicate analysis, spectrophotometry, X-ray diffraction, X-ray spectral study, chemical analysis and electron microscopy. According to the results of studies, the value of silicon dioxide concentration in natural diatomite was determined. It ranges from 72.69% to 78.14%, thus indicating the homogeneity of diatom rocks. Technique to register the absorption spectra (maximum at 305÷335 nm) of amorphous silicon (diatomite) and three oxide components SiO2, Al2O3 and Fe2O3 using a modern spectrophotometer "Evolution 300" was developed. Enrichment of diatomite raw materials was carried out by electrohydraulic method, the essence of which is separation of the clay component using plasma energy arising from a short electric discharge. Electrohydraulic shaking of diatomite and clay mixture leads to their separation. Due to the fact that the density of diatomite is in the range of 380-1000 kg/m3, and clay 1400-1700 kg/m3, the clay, as heavier material settles in the bottom layer, and diatomite concentrates on the top part. As it is shown by the results of chemical, electron microscopic and X-ray fluorescence analysis, after the enrichment of diatomite by electrohydraulic method [1-2], concentration of SiO2 in diatomite increased markedly ? up to 80-85%, and concentrations of Al2O3 and Fe2O3 decreased to 3%. Electron microscopic analysis shows that white spots, belonging to clays, disappeared and pure nanoscale meshes, having dimensions between 272 and 420 nm, increased. Enriched diatomite has the widest range of applications as natural nanomaterial in construction, agriculture, medicine, chemical and oil industries [3-5]. This research has been funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08955761). References 1. Yutkin L.A. Electrohydraulic effect and its application in industry // L.: Machine Building. - Leningrad branch. ? 1986. ? 253 p. [in Russian]. 2. Yutkin L.A. Electrohydraulic effect and its application in mining // Construction Materials. ? 1955. ? ? 9. ? P. 13-15. [in Russian]. 3. Ivanov S.E., Belyakov A.V. Diatomite and its applications // Glass and ceramics. ? 2008. ? Vol. 65(1). ? P. 18?21. 4. Elden H., Morsy G., Bakr M. Diatomite: Its Characterization, Modifications and Applications // Asian Journal of Materials Science. ?2010. ? ?2 (3). ? P. 121-136. 5. Myasnikova L., Barmina A., Zhanturina N., Shunkeyev K. Study of characteristics of natural nanomaterial diatomite by electron microscopic method // Bulletin of Karaganda State university. ? 2017. - ? 2(86). ? P.15-21. [in Russian].

Resume : The series of alloys with nominal compositions of Fe80Co3Si2B12Cu1Nb2 and Fe78Co4Si2B14Cu1Nb1 (at.omic %), were prepared by arc melting of high-purity elements (Fe, Co, Si, Cu, Nb) as well as Fe-B prealloy, in the atmosphere of Ar. The rapidly quenched ribbons were prepared by single roller melt spinning method. Transmission electron microscopy was used for acquisition of atomic structure images, chemical composition, bonding information, internal electromagnetic fields and optical information. The wealth of information on physical, chemical, electronic, optical and magnetic properties on the atomic scale is a key to materials research and future technological developments. The magnetic properties of the alloys were studied at room temperature using hysteresis loop tracer and vibrating sample magnetometer. Optimization of composition of the alloys was carried out to obtain high saturation induction (Bs) and low coercivity (Hc). An attempt to correlate the alloy composition, ribbon thickness, structure and magnetic properties was made. The thickness of the ribbons was between 20 and 36 ?m. To obtain nanocrystalline ribbons, a series of 1 hour annealings were carried out at temperature ranging from 380 ºC up to 550 ºC. The temperature of crystallization stages depends on chemical composition, as expected. The optimum annealing temperature (Ta) of the alloys studied is between 475 °C and 575 °C. The microstructure of the obtained samples was studied by transmission electron microscopy. All samples consist of bcc Fe(Si) crystalline phase and the remaining amorphous matrix. After annealing at the optimum temperature (T=525ºC), in the Fe80Co3Si2B12Cu1N2 alloy shown bright field image (BF), dark field image (DF) from reflex (110) and circular electron diffraction (SADP) revealed that the crystalline phase was bcc-Fe, with the grain size of about 10 nm. Measured interplanar distances (d) were of: d1 = 2.02 Å, d2 = 1.42 Å, d3 = 1.17 Å, d4 = 1.02 Å, d5 = 0.9 Å. They correspond to theoretical distances in Fe (Im-3m): d1 = 2.027 Å, d2 = 1.433 Å, d3 = 1.17 A, d4 = 1.013 Å, d5 = 0.906 Å. Slightly lower values obtained for the studied alloy indicated that there was a small amount of Si substitutionally dissolved in bcc-Fe. On the FFT, observe the reflections from the 110 Fe ? planes, which are visible on the reverse transform in a grain size of about 10 nm. In the Fe78Co4Si2 B14Cu1Nb1 alloy, after annealing at the optimum temperature (T=500ºC) nanocrystals were also found. After analyzing the microstructure of the samples, the small grain size and the nanocrystal structure of the samples were confirmed.

Resume : Atomic force microscopy (AFM) has considerable resolution for imaging and characterization of adsorbed surface nanostructures. However, interpreting images of complex 3-dimensional adsorbates can be difficult and atomistic simulations are often required to provide insight. The most stable simulated structures correspond to the minima of the computed potential energy surface (PES). In the case of complex adsorbates, thorough exploration of the PES with quantum mechanical methods such as density-functional theory (DFT) is prohibitively expensive. We combine DFT with Bayesian inference for global atomistic structure search of the most stable adsorbates. Bayesian Optimization Structure Search (BOSS) [1, 2] is a new artificial intelligence tool, which accelerates the structure search via a strategic sampling of the PES. BOSS computes the complete PES with minimal number of expensive DFT simulations. This allows a clear identification of the most stable minimum energy structures and the barriers between them. We apply BOSS to study the adsorption of (1S)-camphor on the Cu(111) surface as a function of molecular orientation and translations [3]. We identify 8 unique stable adsorbates, in which camphor chemisorbs via an oxygen bond (global minimum) or physisorbs via hydrocarbon interactions to the Cu(111) surface. We employ the most stable structures to produce simulated AFM images, which we use to identify adsorbate configurations in AFM experiments by comparing image features [4]. Via this method, we established that different experimental AFM images of adsorbed camphor correspond to three distinct adsorbate species. This study demonstrates that the new cross-disciplinary tools allow us to identify complex surface nanostructures and properties, and ultimately tune the functionality of advanced materials. [1] M. Todorovi? et al., npj Comput. Mater. 5, 35 (2019). [2] https://gitlab.com/cest-group/boss [3] J. Järvi et al., Beilstein J. Nanotechnol. 11, 1577-1589 (2020). [4] J. Järvi et al., in preparation. Preprint available at Research Square 10.21203/rs.3.rs-50783/v1.

Resume : The paper suggests the novel technique to monitor quality and reliability of thin nano-scale dielectric films. The method presents the modified ramped current stress technique (J-Ramp). Present time in MOS technology of integrated circuits fabrication in order to monitor quality on thin dielectric films, the J-Ramp technique, which detailly described in JESD35-A (JEDEC standard), is extensively utilized. As for the traditional J-Ramp technique, the accumulated charge density, passing through the dielectric at the detection of breakdown (Qbd), is the main parameter characterizing reliability of thin dielectric film. In accordance with the standard, conclusions on reliability of a gate dielectric are based on statistics of Qbd measurements. However, many MIS devices lose functionality not at the time of breakdown but much earlier due to the charge degradation of these, which results in an unacceptable shift of the threshold voltage and a degradation of the key electrophysical characteristics. Taking this into consideration, we propose the enhanced J-Ramp technique that suggests to monitor a value of charge injected in the dielectric at which the unacceptable degradation of the main characteristics of MIS device takes place (Qdeg). In order to implement that, the modified J-Ramp technique incorporates the short-time switching to injection by the certain measurement current level (Jm) before the switching to a higher current level. During injection by the measurement level we calculate the voltage shift across MIS structure. We choose Jm current density on the basis of at that amplitude we should not detect the noticeable charge degradation of the dielectric and the switching to the level should not influence on J-Ramp tests. The switches allow to obtain time dependence of the voltage change across MIS structure at the constant value of injection current Jm for all the range of current stress and, from the dependence, calculate Qdeg and other parameters characterizing charge effects taking place in the dielectric film. Realizing joint analysis of statistical distribution of MIS structures by Qbd and Qdeg, we can estimate quality and reliability of thin dielectric films of certain MIS devices and integrated circuits more complexly and with higher precision.

Resume : Currently, SiO2 films on SiC substrates are used for the production of high-voltage metal oxide semiconductor field effect transistors (MOSFETs). The electrical and structural properties of the oxide depend on the conditions of the oxidation process and may strongly affect the devices performance. In this work, secondary ion mass spectrometry (SIMS) and X-ray reflectivity (XRR) have been used to determine the effect of oxidation temperature on the inhomogeneity of chemical composition and density in nanometric SiO2 films grown on n-type 4H-SiC by thermal oxidation in dry oxygen. Within the films grown at 1000 ? 1100°C with thicknesses of 7.2 ? 20 nm, we have revealed three sub-layers with various densities corresponding to various distributions of the Si, O and C concentrations. The aim of this contribution is to demonstrate an effect of the SiC thermal oxidation temperature on the inhomogeneity of nanometric SiO2 films properties. We combined the measurements by SIMS method and the XRR technique to reveal both of inhomogeneity the oxide layer. The obtained results showed that there is close dependence between the chemical composition and the properties of oxide which strongly depend on temperature of process. Acknowledgements: This work was supported in part by the National Centre for Research and Development under Research Grant Agreement TECHMATSTRATEG1/346922/4/NCBR/2017 for the project ?Technologies of semiconductor materials for high power and high frequency electronics?. Pawe? Piotr Micha?owski was additionally supported by the National Science Center (NCN) within SONATA 14 2018/31/D/ST5/00399 project "Secondary Ion Mass Spectrometry characterization of thin films with nanometer and subnanometer depth resolution" Rafa? Budzich acknowledges financial support from IDUB project (Scholarship Plus programme).

Resume : Single nano-entity electrochemistry requires high-resolution and high-bandwidth current amplification due to the low magnitude and short duration of the current signals.[1] However, increasing the current amplifier bandwidth leads to increased current noise levels, which in turn obscures the current signal generated from single nano-entity electrochemistry experiments.[2] Noise levels are very sensible to the input capacitance of the current amplifier when operating at high bandwidth.[3] In this poster we introduce a new strategy to minimise the input capacitance to a current amplifier for stochastic collision electrochemistry. This is achieved by using a movable microscale electrochemical cell, formed at the end of a micropipette using a scanning electrochemical cell microscopy approach,[4] to conduct electrochemical experiments in close proximity (~300 µm) to a custom design transimpedance amplifier. We demonstrated this via electro-oxidation of single Ag nanoparticles detected at 1 MHz bandwidth. [1]. Kang, M. et al. Langmuir 32, 7993?8008 (2016). [2]. Patrice, F. T. et al. Annu. Rev. Anal. Chem. (2019). [3]. Djekic, D. et al. IEEE International Symposium on Circuits and Systems, 842?845 (2016). [4]. Ebejer, N. et al. Ann. Rev. Anal. Chem. 6, 329?351 (2013).

Resume : The contact resistance increase that occurs at the source/drain (S/D) metal/semiconductor interface within a MOSFET is a significant hindrance to the downscaling of logic devices for the upcoming technology nodes [1]. For pMOS devices, boron-doped Si1-xGex is currently the standard material for S/D regions. This is because its larger lattice parameter compared to that of Si induces a compressive strain within the channel region. This has the beneficial effect of enhancing hole mobility. Furthermore, SiGe can also attain a high active in-situ B-doping level (above 1E21 at./cm-3) [2], which is conducive for achieving a low contact resistivity (rho-c). However, to keep the parasitic resistance sufficiently low, when contact areas are reduced, the level of active doping needs to be even higher. New doping elements are being researched as potential candidates to complement or replace B. Ga is a promising option. Thanks to its covalent radius larger than B, it contributes to an increase of the lattice mismatch against Si. Moreover, several literature reports already presented successful examples of low rho-c values (< 1E-9 ohm.cm^2) attained with Ga-doping in Si1-xGex [3]. These reports usually claim that dopants segregation is key for the engineering of ultimate contacts. However, a clear characterization and understanding of the mechanisms into play seems missing. In this contribution, we report on the study of in situ B and Ga co-doped Si1-xGex layers with a nominal Ge content of x = 0.45. Chemical composition profiles are obtained using secondary ion mass spectrometry (SIMS). SIMS profiles typically show a graded Ga profile, with a higher atomic concentration close to the free surface. However, a comparison with SIMS spectra measured after a post-growth surface clean demonstrates that strong Ga segregation occurs during the epitaxial growth with very limited amounts of Ga being incorporated in the epitaxial layer. The graded profiles measured for as-grown samples are, in fact, created by the recoil mixing due to the incident ion beam on the Ga-rich layer present at the sample surface. Flat and real Ga profiles, which are not affected by post-deposition clean, have been measured for in-house developed growth process based on extremely low growth temperatures and higher-order precursors. References: [1] S. Mao and J. Luo, J. of Physics D: Applied Physics 52(50), p. 503001 (2019) [2] R. Loo et al., ECS J. Solid State Sci. Technol., 6(1), pp. P14?P20 (2017) [3] J. L. Everaert et al., Dig. Tech. Pap. - Symp. VLSI Technol., 0(6), pp. 214?215 (2017)

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 : Antiferromagnetic thin films attract significant interest for future low-power spintronic devices. They are largely insensitive to external magnetic fields, exhibit domains with negligible cross-talk and they can be switched at THz frequencies [1]. Furthermore, in multiferroics where antiferromagnetism can coexist with ferroelectricity, it is possible to control the magnetic state electrically - a particularly appealing feature for future device applications. [2] In this talk, we show how the Qnami ProteusQ? - a commercial room temperature scanning nitrogen-vacancy magnetometer (SNVM) can be used to quantitatively image antiferromagnetic spin textures with proven dc field sensitivity 0.02 Gauss/Hz^(0.5). We image the exotic spin cycloidal textures of multiferroic bismuth ferrite (BiFeO3) thin films using two different imaging modes (iso-B mode and full-B mode) and extract a period of ~100 nm. In addition, we take advantage of the quantitative nature of SNVM to extract an average magnetic moment density of 0.08 +/-0.02 uB /Fe in the BiFeO3 film. These findings agree well with reported vibrating sample magnetometer results (MS = 0.06 uB /Fe) on similar, strained BiFeO3 thin films. [3] Our results shed the light on future design requirements for reconfigurable nanoscale spin textures on such multiferroic systems. Our technique is suitable for the metrology of future spintronics devices. [1] V. Baltz, et al., Rev. Mod. Phys. 90, 015005 (2018). [2] A. Haykal, et al., Nat. Commun. 11, 1704 (2020). [3] W Eerenstein, et al., Science 307, 1203a (2005).

Resume : A key driver for avoiding greenhouse gas emissions is the success of green technologies especially in the energy sector. In order to bring these products and technologies as fast as possible to a market-ready and competitive state, advanced and adapted metrology is urgently needed. Technically verifiable methods and standards are required to master the challenges of the energy transition and to provide an important anchor of trust in these technologies for the society of a joint Europe. This can only be achieved together with the players involved from policy, industry, engineering, and research. Therefore, our consortium of European national metrology institutes is planning to establish a European Metrology Network (EMN) on Clean Energy within the framework of the European Association of National Metrology Institutes (EURAMET). The EMN will summarise the requirements for metrology resulting from political framework conditions and technology roadmaps into strategic research agendas for the clean energy metrology landscape. Already in the foundation phase of this network a unique point of contact for stakeholders will be provided for all metrological issues at European level in the field of clean energy, such as for photovoltaics, wind, power conversion, like Power2X, fuel cells, biomass, and energy storage materials. The project and the stakeholders will benefit from the scientific excellence of the European metrology institutes in the fields of material research, legal metrology, regulation and standardisation by providing unique facilities for research and services, by promoting best practice, and by the creation and dissemination of knowledge. Here we present an overview of our project which will be kickstarted in May 2021. The early and most complete evaluation of all relevant stakeholder interests and needs - including the research community for energy materials - is the projects starting point, being at the core of the related roadmap generation processes. The topics of interests with respect to the need are detailed below: - A more complete understanding of degradation, aging processes, and durability of materials, - In-situ / operando characterisation and measurement techniques, - Hybrid / multidimensional characterisation and measurement techniques, - Improvement of calibration standards (e.g. samples) and reference measurement techniques, - Characterisation techniques under dynamic conditions, - Measurement methods to rate the energy system efficiency, - Metrology for single elements such as wind turbines, PV, battery storage, as well as coupled energy systems.

Resume : Nanoparticle size impacts properties vital to applications ranging from drug delivery to diagnostics and catalysis. As such, evaluating nanoparticle size dispersity is of fundamental importance. Conventional approaches, such as standard deviation, usually require the nanoparticle population to follow a known distribution and are ill-equipped to deal with highly poly- or heterodisperse populations. Herein, we propose the use of information entropy as an alternative and assumption-free method for describing nanoparticle size distributions. This measure works equally well for mono-, poly-, and heterodisperse populations and represents an unbiased route to evaluation and optimization of nanoparticle synthesis. We provide intuitive software tools for analysis and supply guidelines for interpretation with respect to known standards.

Resume : In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. The use of suited reference nanomaterials is part of this challenging task. Furthermore, the European Commission?s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ? 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution. These reference materials will also target other key parameters like shape, structure, porosity, or functional properties, for which the lack of available suited reference nanomaterials is even more critical. Particularly for the imaging by electron microscopies, new nanoparticles of other materials than the available silica, polystyrene, Au, or Ag with well-defined size in the range of 10 nm are decisive for the accurate particle segmentation by setting precise thresholds. In this respect, monodisperse iron oxide nanoparticles synthesized at BAM are considered as a reference material candidate for particle size measurements. Iron oxide nanoparticles can be provided in large quantities by the thermal decomposition of iron oleate precursors in high boiling organic solvents with adaptable size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. The particles synthesized at BAM cover the size range of 6-12 nm in cubic as well as spherical shapes. Narrow monodisperse size distributions as well as slightly broader particle size distributions can be realized in a reproducible manner. Electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM), atomic force microscopy and dynamic light scattering techniques have been used to assess the size distributions revealing good agreement between the methods. In future, thorough investigation of the long-term stability, surface characteristics (morphology and chemistry), magnetic properties and complete metrological characterization will be performed. Furthermore, ligand exchange procedures to yield water dispersible iron oxide nanoparticles are under investigation to include methods like differential mobility analyzing or single particle ICP-MS for particle characterization. [1] J. Park et al. Nature Materials 2004, 3 (12), 891-895. [2] M. Kovalenko et al. Journal of the American Chemical Society 2007, 129 (20), 6352-6353.

Resume : Energy harvesting from renewable sources (solar, heat and movement) is a prominent solution to create small amounts of electrical energy in areas of difficult access. Due to their extremely small physical size and high surface to volume ratio, nanowire (NW) based energy harvesting systems, including photovoltaic solar cells, thermoelectrical and electromechanical energy nanogenerators, have gained tremendous interest and encouraging progress has been achieved. In particular, it has been confirmed that the efficiency of NW solar cells can be enhanced from 17.8 % currently to its ultimate limit of 46.7% by means of nanophotonic engineering. However, due to nanometre dimensions of the wires and large size (m2) of the devices, they also bring challenges for testing and characterisation. For example, the quantitative link and correlation between the performance of a single NW and that of the overall device is still missing. Moreover, no reliable metrology for large area NW arrays (from cm2 to several m2) with diameters between 50 nm and 1 µm is currently available. Quality control of these energy harvesting systems is highly challenging, and high throughput metrology is necessary, which requires the development of traceable measurement methods and models for the characterisation of NW energy harvesters, solar cells and devices. This project aims to solve these issues by developing reliable and high throughput metrology for the quality control of NW energy harvesting systems.

Resume : The CHALLENGES project has the ambitious goal to advance the state-of-the-art in the field of nanoscale real-time characterization of industrial nano-enabled materials and devices and related metrology techniques. The project aims to develop real-time non-destructive techniques for reliable nanoscale in-line control, nowadays not available, during manufacturing. The innovations introduced by CHALLENGES will be developed by exploiting the plasmonic enhancement of optical signals and will result in metrology technologies with increased speed, sensitivity, spectral range, and full cleanroom compatibility within different production environments. This will allow overcoming current limitations of existing techniques, like Raman, InfraRed (IR), Photoluminescence (PL) spectroscopy, that do not have typically enough resolution for the detailed characterization of nano-scaled devices. CHALLENGES approach will be demonstrated and validated on relevant industrial applications in the field of 2D Materials, Semiconductor Industry, and Si Photovoltaics. Overall, the achievement of CHALLENGES objectives will significantly empower industry competitiveness reducing the time and resources needed for nanomaterial development and upscaling. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 861857.

Resume : Background: Combined hyperthermia & radiotherapy treatment characterisation is limited by a lack of biomarker quantification, the antibody specificity of flow cytometry and the availability of high throughput gene analytics. A novel multimodality spectroscopy procedure has been developed to probe biomarkers in X-irradiated mouse tissues. Methods: 10 mm thick cryosections, extracted 72 h after exposure to 2 or 6 Gy X-rays on a Small Animal Radiation Research Platform (SARRP), were mounted on mid-infrared (MIR) low-e-glass slides. Non-invasive, stain-free probing techniques (X-ray fluorescence (µ-XRF); Fourier transform infrared µ-spectroscopy (µ-FTIR); Nanoscale IR Spectroscopy (AFM-IR); Matrix assisted laser desorption ionisation (MALDI); mass spectrometry imaging (MSI)) were used. Results: Hyperspectral data from normal liver have characteristic MIR fingerprints arising from proteins, lipids, and DNA. MSI measurements post µ-FTIR analysis were registered with corresponding IR data and correlation analysis performed. Mass:charge images, (highly correlated with IR microscopy images) were matched to the human metabolome database (HMDB). XRF µ-mapping gave the element spatial distribution. Biomarker quantification used reference-free X-ray spectrometry. Conclusion: A novel multimodality spectroscopy method of characterising biological tissues has been developed. This offers greater sensitivity, selectivity and biomarker quantification potential than traditional techniques.

Resume : Recently, iron oxide nanoparticles (NPs) have been extensively studied for therapeutic applications, like magnetic hyperthermia. Their capability to generate heat when exposed to ac magnetic fields is usually measured via the specific loss power (SLP), which expresses the power dissipated per unit mass of magnetic material. The SLP can be increased in presence of hysteresis losses, which typically appear for NP sizes larger than 20 nm and can be properly tuned by varying NP dimension and shape. Additional effects that can influence the hysteresis losses are the magnetostatic interactions among NPs, which strongly depend on their aggregation state. In this context, we present a detailed study of cubic iron oxide NPs, with size in the range 30-200 nm, to elucidate their potential use in magnetic hyperthermia. The NPs were prepared via hydrothermal route and then structurally and dimensionally characterized by combing XRD, SEM and TEM information. Magnetometric measurements were performed to analyze hysteresis contribution versus NP size and state of aggregation. This experimental study was supported by micromagnetic modelling with the aim of calculating the NP hysteresis loops with a theoretical approach based the Landau-Lifshitz-Gilbert equation. Finally, calorimetric experimental and modelling characterizations were carried out at 100 kHz, evidencing good heating performance, with SLP values in the order of 100 W/g.

Resume : A very novel technique for the production of tiny particles with different composition is spark ablation which uses repeated sparks produced between two electrodes. These sparks heat the electrodes to their boiling point in an extremely fast way resulting in vapour containing metal ions which when mixed with a carrier gas (usually an inert gas) leads to instantaneous cooling and the creation of tiny nano-particles (3-5 nm) which can be deposited on a substrate of interest. We used this technique to prepare small nano-particles composed of Pd-Fe2O3, which were subsequently analysed by means of X-ray fluorescence (XRF) based methods. Here, a reference-free approach [a] was selected which allows for quantifying the elemental composition of the particles produced based solely on the use of (radiometrically) calibrated instrumentation and the knowledge of atomic fundamental parameters. From grazing incidence X-ray fluorescence measurements, the size of the nanoparticles can be extracted by modelling the dependence of the XRF intensity on the incidence angle which is varied around the critical angle for total external reflection [b]. GIXRF measurements were enabled by the selection of a suitable substrate such as Si wafers.. Furthermore, the chemical binding of Fe was probed by means of near edge X-ray absorption fine structure (NEXAFS) measurements. [a] B. Beckhoff, J. Anal. At. Spectrom. 23, 845-853 (2008) [b] Y. Kayser et al., Nanoscale 7, 9320 (2015)

Resume : In the last decade, magnetic materials like superparamagnetic iron oxide nanoparticles have been intensively studied for potential application in cancer therapies based on hyperthermia. Recently, single- and multi-domain ferromagnetic nanostructures turned out to offer an improved heating efficiency due to hysteresis losses, that can be increased through the modification of nanostructure shape. To this aim, nanodisks offer the possibility of obtaining large hysteresis losses and magnetic vortex configuration at remanence, with consequent reduction of agglomeration effects. In this framework, the present work focusses on Fe-Pd nanodisks, prepared by self-assembling nanosphere lithography, that display a vortex magnetic configuration. The hysteresis losses generating heat can be tailored by controlling nanodisks size. Therefore, Fe-Pd nanodisks with different diameters have been produced and magnetically characterised, obtaining their hysteresis loops and energy dissipation per cycle. The experimental results have been supported by a micromagnetic modelling analysis based on the Landau-Lifshitz-Gilbert theory, conducted on nanodisks in 2D array arrangement (attached on substrate) as well as dispersed in liquid. This study has enabled us to select the nanodisk size more indicated for hyperthermia application and to elucidate the role of magnetostatic interactions on the heating performance.

Resume : Following a long line of successful publications of the previous ALTECH 2014 and ALTECH 2017 E-MRS Symposia, we publish once again a Special Issue in pss (a) – applications and materials science highlighting the exciting results of this E-MRS 2021 M Symposium. physica status solidi is one of the largest and well-established publication platforms in solid state, applied, and device physics, as well as, materials science with more than 1000 articles per year – now close to 60 years in business – and widely accessible as part of many national and institutional site licenses. Evidenced by many hundreds of thousands of article downloads annually, the publication in physica status solidi will make your important works available to a large international audience quickly. Moreover, the publications of your paper in physica status solidi includes the following further benefits: No page charges or publication costs for authors; modern article formats (PDF, Enhanced PDF, HTML, Enhanced Article for mobile devices) and a Wiley OnlineOpen option compliant with funder mandates and supported by many institutions. Furthermore, physica status solidi is indexed in ISI Web of Science and all other major abstracting databases.

Resume : X-ray spectrometry is a widely used non-destructive analytical technique for the investigation of various kinds of materials in many fields of research important for addressing the main global challenges such as in Energy, Nanoelectronics, Health, and Environment as well as for the preservation of Cultural Heritage. X-ray fluorescence techniques are used qualitatively as well as quantitatively for sensitive and simultaneous elemental analysis. EXSA is a non-profit organization founded in 2004 for promoting cooperation and scientific exchanges between X-ray spectroscopists and analysts within Europe. It brings together users of X-ray spectrometry in various fields of research as well as manufacturers of X-ray instrumentation and developers of X-ray methodologies. EXSA aims to stimulate interaction and communication between young and experienced scientists, between academia and industry, thus fostering scientific progress and innovation. EXSA awards scientists for their exceptional contributions to the field of X-ray spectrometry on the level of young scientists and for outstanding scientific achievements. EXSA supports the participation of young scientists in conferences and organizes summer schools as well as workshops on novel and emerging XRS topics. EXSA gathers more than 120 members from academia and industry and is sponsored by more than 10 companies. So far EXSA has supported more than 50 workshops and conferences, among them the all E-MRS symposia of the ALTECH series.

Resume : In the past decades the use of synchrotron radiation sources was a driving force for building up and establishing new X-ray methods. These X-ray methods expanded the options to probe and investigate chemical, structural and even dynamic properties of a large variety of samples. The power of these methods attracted and attracts a growing user community from various fields of research. The demand exceeds the available beamtime by far. In addition, for many research questions the access on a day-by-day basis for more than a week is desirable or even mandatory. In order to enlarge the use of modern X-ray techniques and increase the diversity of application fields we transferred successful synchrotron methods to our BLiX-laboratory (Berlin laboratory for innovative X-ray technologies). The talk will present a short overview of transferred spectroscopic methods, which are cryogenic 3D Micro X-ray fluorescence , X-ray absorption spectroscopy in the hard and soft X-ray regime , high resolution X-ray emission spectroscopy , and X-ray microscopy in the soft X-ray regime . The main emphasis will be laid upon spectroscopic and microscopic possibilities for X-ray analysis of nanomaterials.

Resume : Quick-EXAFS adds time resolution to X-rays absorption spectroscopy and thus allows to follow dynamic structural changes of matter. This is of particular interest for the in-situ monitoring of nanomaterials synthesis, where e.g. the structure and the growth of nanoparticles in gaseous or liquid environments can be followed on time-scales from sub-seconds to minutes or even hours. While conventional transmission or fluorescence mode EXAFS are capable to investigate bulk materials only, the use of the grazing incidence geometry provides surface sensitivity, thus enabling detailed structural investigations of thin films and surfaces. Here we will discuss dedicated experimental setups and routines used for time-resolved grazing incidence data acquisition and analysis. Case studies will feature in-situ studies during the sputter deposition of different thin film materials. The analysis of the grazing incidence EXAFS data allows to follow thin film growth on time scales of 50 ms, yielding their structure, surface and interface roughness, as well as their chemical composition. In the case of copper, the surface oxidation of the films induced by air exposure was studied for different temperatures, showing a passivation with Cu(I)-oxide layers of some few nm thickness at room temperature, while oxide layers of several 10 nm thickness are formed for temperatures of 150-250 °C. Future prospects of the time-resolved EXAFS techniques for investigations of nanomaterials will be discussed.

Resume : Controlled silicon nanocrystals (nc-Si) formation in dielectric matrix is promising direction for the opto- and nanoelectronic devices development. One of the ways for nanocrystals size control is the formation of the multilayered nanoperiodical structures (MNS) with fixed thicknesses of nanolayers containing Si nanoparticles between nanolayers of different materials (e.g. ZrO2). The redundant Si in the SiO2 matrix can be obtained by annealing of the SiOx films. Another way to form nc-Si can be annealing of amorphous silicon interlayers. MNS were formed by a-SiOx or a-Si and ZrO2 or Al2O3 or SiO2 layer by layer deposition on to Si substrates with few nanometers thickness respectively of each layer type. The formed structures were annealed aimed at photoluminescent Si nanoparticles formation with fixed sizes. MNS were studied by means of electronic structure and local atomic surrounding sensitive XANES spectroscopy and XPS techniques supported by XRD and SEM. A noticeable changes of electronic structure and phase composition caused by transformation of the Si atoms surrounding is shown depending on MNS properties. High temperature annealing do not always lead to Si nanoparticles formation in MNS formed with a-Si interlayers. Effective interaction between MNS silicon/dielectric layers is studied. The highest temperature anneal of 1100 C can lead to complete MNS destruction. Al2O3 is suggested as best dielectric material for nc-Si arrays formation in MNS.

Resume : Phase transitions and microstructure changes play a crucial role during the fabrication of functional materials such as solar cell films or battery electrodes. Moreover, knowledge of the stability ranges of crystalline phases or decay processes in humid atmosphere are essential to judge on the suitability of a material for a specific task. Real-time and in-situ X-ray analysis has proven as indispensable method to gain these insights in compound materials. However, to analyze the dynamics of rapid phase transitions and microstructure changes, sufficient time resolution is a prerequisite. Synchrotron radiation, which provides high photon fluxes and thus enables high time resolutions, have the drawback of low availability. This imposes a major limitation for time-consuming studies. To solve this limitation, we have developed a laboratory setup based on a high-flux liquid-metal-jet X-ray source, polycapillary optics, a 2D-detector for X-ray diffraction (XRD) and an SDD detector for simultaneous X-ray fluorescence analysis (XRF). In this contribution, we demonstrate the suitability of this setup for time-resolved in-situ/in-operando XRD and XRF studies in the lab. We utilize these capabilities to study phase transformations and decay processes in inorganic perovskite absorber films for solar cells exposed to humid air as well as in Li-S batteries during multiple charge/discharge cycling.

Resume : Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful tool for operando non-destructive interface characterization of functional devices. The use of hard X-ray synchrotron radiation (2.4-12 keV) allows to gather information in regions up to 5 times deeper in the sample than from laboratory sources. This is of particular interest to study the, often critical, buried interfaces of devices covered by thick electrodes. Operando measurements, where a device is biased while performing HAXPES measurements, are therefore, powerful in order to understand the changes in elemental composition and charge distribution inside the device during operation. This approach is of particular interest for dynamical electrical systems such as memory cells based on resistive switching. In the present contribution we focus on the chemical reactions occurring at the M/ LaMnO3 d interface during switching operations and on the influence of the electrode material (M = TiN, Au, Pd) on the redox process taking place. The non-stoichiometric transition metal oxide LaMnO3 d exhibits resistive switching response governed by the oxygen vacancy concentration in the material.[1] Our investigations based on photoemission techniques demonstrate that the change of resistance is triggered by vacancies displacement under an electric field and the concomitant oxygen accumulation. Operando HAXPES experiments performed at Galaxies (SOLEIL)[2] and BL12XU (SPring-8) synchrotron beamlines specifically highlight the strong correlation between the nature of the top electrode (chemically active material or noble metal) and the final characteristics of the memristive device. Based on the combination of in-situ electrical measurements and HAXPES energy shift observations, we propose a comprehensive description of the conduction path in the material and the associated resistive switching mechanism. We also propose an innovative way to use the plain potential of HAXPES for the study of dynamic systems such as resistive switching memories. [1] Meunier et al. ACS Appl. Electron. Mater. 1(5), 675?683 (2019) [2] Meunier et al. J. Appl. Phys. 126, 225302 (2019)

Resume : For small-angle X-ray scattering (SAXS), we propose a novel approach in numerically calculating scattering profiles of arbitrarily shaped nanoparticles by using Debye's scattering formula. Debye's formula allows to calculate elastic scattering pattern of an ensemble of scatterers such as atoms, atomic nuclei etc. in the "kinematic" limit. By generating a virtual point cloud of the desired particle shape, i. e. a particle which is composite of identical sub-particles, an open-source C/C program named DEBYER is then utilized to calculate the corresponding mono-disperse SAXS pattern. To emulate a homogeneous electron contrast of the particle, a three-dimensional (3D) mesh of the particle's shape is filled by virtual scattering points to build the 3D cloud. This is a key feature of our proposed method because it eventually allows to reduce computational time. Furthermore, our method enables us to easily re-scale the calculated mono-disperse SAXS pattern to account for different particle sizes. As a result, we can construct poly-disperse SAXS pattern by superposing re-scaled mono-disperse SAXS profiles and thus we are able to fit and analyze experimental data of diluted colloidal suspensions of nanoparticles. We want to demonstrate the manifold opportunities of our work by first comparing analytically and numerically calculated SAXS profiles of common particle shapes. Thereafter we will introduce various models of cubic particles to characterize cubic Au nanoparticles based on the underlying free fitting parameters.

Resume : A reliable and non-destructive characterization of the material composition and dimensional parameters of the nanostructures is needed for the production of the current and next generation semiconductor devices. A metrology technique based on grazing incidence X-ray fluorescence measurements is applied here to lamellar nanoscale gratings made of Si3N4 and SiO2. The X-ray standing wave field, which arises due to interference between the incident and the reflected radiation, is used as a nanoscale sensor in this technique. Depending on the elemental composition and dimensional parameters of the nanostructures, distinct angular dependent fluorescence signals are observed when the sample is rotated with respect to the incident radiation. The X-ray standing wave field can be calculated with a finite element Maxwell solver in order to model the experimental data using a parameterized model of the nanostructure. This modeling allows to derive the spatial distribution of elements and the geometric shape with sub nanometer resolution. The computational effort of such a reconstruction can be very big depending on the dimensional parameters of the nanostructure. With a Bayesian optimization approach this effort can be kept at a reasonable level. We demonstrate the characterization of different lamellar Si3N4 and SiO2 grating structures.

Resume : Resonant inelastic X-ray emission (RIXS) provides detailed insight into the electronic structure of molecules and materials. Using RIXS in the soft X-ray range, chemical speciation methodologies can be used to investigate light elements. In addition, theoretical modeling techniques can be used to interpret the data and the various features of RIXS maps. Molecules with a similar structure but one differing atom such as cyanates and thiocyanates provide good probes for the analysis of the influence of chemical bonds on the electronic structure of materials. In this work, cyanate and thiocyanate were investigated at the plane-grating monochromator (PGM) beamline at the electron storage ring BESSY II. A high-resolution wavelength-dispersive X-ray spectrometer (WDS) based on the Rowland geometry was used [1], whereby calibrated instrumentation allowed deconvoluting the spectra and differentiate between experimental and physical contributions. Using this approach, a comparison to calculations of core-level spectroscopy based on ground-state (DFT) calculations [2] and the Bethe-Salpeter equation using the OCEAN code [3, 4] is enabled. The presented study provides an in-depth analysis of the electronic structure of cyanates and thiocyanates and explores the possibility to probe ground state vibrational properties using RIXS. However, due to long acquisition times radiation damage must be included in the analysis. Therefore, complementary near edge X-ray absorption measurements were realized to investigate radiation dose dependent effects. [1] M. Müller et al., Phys. Rev. A 79, 032503 (2009) [2] https://quantum-espresso.org/ [3] K. Gilmore, J. Vinson, E. L. Shirley, D. Prendergast, C. D. Pemmaraju, J. J. Kas, F. D. Vila, J. J. Rehr, Comp. Phys. Comm. 197, 109 (2015) [4] J. Vinson, J. J. Rehr, J. J. Kas, and E. L. Shirley, Phys. Rev. B 83, 115106 (2011)

Resume : It is known that the TXRF procedure shows the best element diagnostic results at material surface layers study and the PIXE spectrometry is the most sensitive X-ray fluorescence method for bulk element concentration analysis. However, the planar X-ray waveguide-resonator (PXWR) including into TXRF measuring scheme allows to decrease pollution detection limits on two orders [1] and this device use in frame of PIXE investigations permitted to elaborate new effective method for the surface element diagnostics [2]. There are presented experimental data verifying the TXRF measurements analytical sensitiveness abrupt increasing. It is discussed possibilities of TXRF-PIXE new analytical method built on base of PXWR application and it is presented its comparison with the modified TXRF technology. [1] V.K. Egorov, E.V. Egorov, E.M. Loukianchenko. High effective TXRF spectrometry with waveguide-resonance device application // Aspects Min. and Min Sci. v2(4) (2018) 1-23. [2] M.S. Afanas?ev, V.K. Egorov, E.V. Egorov and all. The total reflection X-ray fluorescence yield formed by a waveguide-resonator under conditions of ion beam excitation // Instruments and Exp. Tech. v62(5) (2019) 659-663.

Resume : In the field of ferroelectrics, the heteroepitaxial growth of complex oxides has enabled materials to be created in which the strain and the polarization, electric gradient and elastic energies and be tuned. Competition between these energy terms produces competing ferrotoroidic phases which manifest as structural domains of polar flux-closure topologies, vortices and skyrmionic structures. Superlattices also allow tailoring of the layer parameters to modify the structure-energy relationships. Detailed research efforts are now underway to understand the underpinning physics and explore potential applications. Critical to this effort are detailed structural studies and new metrology pathways to quantify the topologies found. In this presentation we will have explore epitaxial superlattices grown on DyScO3 with ferroelectric PbTiO3 and different spacers; paraelectric insulators (SrTiO3, and TbScO3) and metallic SrRuO3. We observe domain structures that clearly depend on the nature of the spacer layer, the thickness of the ferroelectric layer, the ratio of ferroelectric to spacer layer thickness and the total number of repeats. The parameter space is explored using both laboratory and synchrotron high resolution double axis x-ray diffraction through satellite diffraction arising from the topological states observed. We present a metrology which enables the topologies to be quantified and benchmark our findings using TEM analysis.

Resume : The value of elemental analysis depends upon the level of confidence that can be placed in the results. Adopting good laboratory practices, standard operating procedures, metrology and quality principles help in maximizing the reliability of the results. TXRF is one of the most impressive analytical technique providing spectral signatures of materials that unravel their elemental composition and surface contamination. Within seconds and limited sample preparation, a qualitative characterization can be obtained, whereas thorough and quantitative information requires a full experimental design approach. Also, tiny variations in the experimental conditions may cause fine spectral differences that may be difficult to identify, but affect tremendously the validity of the results. Per se and despite its apparent versatility and ease-of-use, many issues remain opened in TXRF analysis. These are lying from sample preparation procedures and requirements (e.g. very flat substrate as Si wafer, nanostructures deposited on wafer), instrumentation and experimental conditions to data analysis and standardization, and prevent the spread of TXRF in chemical and material analytical communities. To counteract, some European initiatives (e.g. CA 18130 https://enforcetxrf.eu) are reflecting on TXRF current challenges and defining a realistic road map establishing the correct conditions for TXRF analysis and its domains of applicability, while joining chemical and physical traceability approaches.

Resume : X-rays from brilliant synchrotron sources are widely exploited in materials research already for decades providing the unique possibilities to probe structural, electronic and magnetic properties of different types of materials and their dynamic characteristics in the element-specific way with an appropriate time resolution. Further development of synchrotron facilities worldwide offers new scientific opportunities for frontier studies related to novel materials and their functionality as well as further progress in the improvement of measurement techniques and detection procedures. BESSY III designed by Helmholtz-Zentrum Berlin and its strategic partners will be a globally competitive synchrotron radiation large-scale user facility in the field of XUV, soft and tender X-rays for research and industry. A particular aspect of Materials Metrology within the BESSY III project is accompanied by the Physikalisch-Technische Bundesanstalt, Germany's National Metrology Institute. The role of Materials Metrology in studies of new functional materials, e.g. for quantum information technology, effective solar cells manufacture, batteries improvement, smart coatings, etc., is currently under active discussions. The implementation of established procedures of standardized and validated measurements with SI-units traceable quantities as well as advanced instrumentation will provide BESSY III user community more possibilities for trustworthy and reliable studies.

Resume : Laser-induced breakdown spectroscopy (LIBS) is a powerful elemental analysis method thanks to the negligible sample preparation, rapid detection, and a spatially resolved sensitivity down to trace level in any kind of sample matrix. Conventional LIBS is operated in the UV-visible spectral range (LIBS-OES), where the results are limited by the low stability and repeatability of the plasma emission. This is particularly critical for spatially resolved analysis at nano-scale, where the sample heterogeneity is affected by the measurement precision. Utilization of the plasma emission in the extreme ultraviolet (XUV) wavelength range proved to fully overcome such limitations. LIBS-XUV was applied to quantify lithium in energy materials, where the distribution of this element plays an important role for the functionality, for instance, in battery technology. The LIBS-XUV signals proved one order of magnitude more stable than for LIBS-OES by comparing the spectra of lithium fluoride (LiF) from 20 laser shots in single-shot mode. In addition, the effect of the slit width on the LIBS-XUV results was also investigated, where 50 µm slit width showed the best performance. Moreover, a series of calibration samples Li2O/MnxOy were processed with LIBS-XUV to obtain the Li concentration calibration function for the quantitative analysis. By using the obtained calibration function, one can also determine the Li concentration in a Li-Mn battery. The 3s-limit of detection of Li was calculated to be 144 ppm. Finally, an effective method of "rapid fingerprinting" using the oxide signal in LIBS-XUV will be discussed.

Resume : The unambiguous correlation of possible health and sustainability risks to nanoparticle size must be enabled by reliable measurement of nanoparticle size, to ensure comparability and compatibility between results measured under different methods. The NPSIZE project funded by European Metrology Program (EMPIR) develop methods, reference materials and modelling to improve the traceability chain, comparability and compatibility of nanoparticle size measurements. In this work, we present how spherical silica nanoparticles are synthetized with controlled monomodal or bimodal dispersion to be use as reference materials and international round-robin. Improving the fabrication requires a fine understanding of synthesis (1), coupled with an expertise of in-situ or ex-situ analysis methods. This is a new challenge for the analysis : determining not only average characteristics (size, chemical composition and shape ...) but also the concentration and the distribution over the population studied (2). Small-Angle X-ray Scattering (3) allows very precise measurements of the nanoparticles size and concentration that can be directly link to the metric system (4) (metrological traceability) . We developed a SAXS laboratory instrument dedicated to the in-situ characterization of nanoparticles, which enable fast measurements, and the monitoring of the synthesis parameters. Measurement protocols and software processing chain (5) (i.e. size distribution) are also combined & optimized. 1- Sarah Fouilloux et al., « Nucleation of Silica Nanoparticles Measured in Situ during Controlled Supersaturation Increase. Restructuring toward a Monodisperse Nonspherical Shape », Langmuir 27, no 20 (18 octobre 2011): 12304?11, https://doi.org/10.1021/la2013842. 2- Valérie Geertsen et al., « Contribution to Accurate Spherical Gold Nanoparticle Size Determination by Single-Particle Inductively Coupled Mass Spectrometry: A Comparison with Small-Angle X-Ray Scattering », Analytical Chemistry 90, no 16 (21 août 2018): 9742?50, https://doi.org/10.1021/acs.analchem.8b01167. 3- Olivier Taché et al., « MOMAC: a SAXS/WAXS laboratory instrument dedicated to nanomaterials », Journal of Applied Crystallography 49, no 5 (1 octobre 2016): 1624?31, https://doi.org/10.1107/S1600576716012127. 4- ISO 17867:2015, « Particle size analysis ? Small-angle X-ray scattering », s. d. 5- I. Bressler, B. R. Pauw, et A. F. Thünemann, « McSAS: software for the retrieval of model parameter distributions from scattering patterns », Journal of Applied Crystallography 48, no 3 (juin 2015): 962?969, https://doi.org/10.1107/S1600576715007347.

Resume : Ellipsometry is a highly sensitive optical surface analysis tool. Due to its unique properties as a method, it is fast, easy to implement and highly scalable while remaining one of the most surface sensitive methods. In this presentation, we will report on the current state of standardised measurements with ellipsometry and on best practices for using it to determine surface properties. This field has proven to be very difficult in the past as ellipsometry usually relies on model-based data analysis. Extensive work is currently done to describe ellipsometry as a method with respect to quantified accuracy as well as traceability. This work is in parallel done for specific classes of samples and with a generalised sample-independent approach, as demonstrated in DIN 50989-1 and ISO CD 23131. We present the current description of the method with respect to standardisation and accuracy and show its usefulness with a collection of examples involving complex analysis work. We use these examples from internal and laboratory comparison projects to show how ellipsometry can be performed in a traceable way and to explore how measurement uncertainties can be calculated. Finally, we will introduce a best practice guide developed by the EMPIR HyMET project on how to measure complex surface parameters by means of a multi-method approach.

Resume : Infrared photocurrent mapping has rapidly developed in recent years. Here we present a near-field induced contrast mechanism arising when a conducting surface, exhibiting a magnetic moment, is exposed to a nanoscale heat source. The magneto-caloritronic response of the sample to near-field excitation of a localized thermal gradient leads to a contrast determined by the local state of magnetization. The impact of this finding is threefold: 1) It allows non-invasive imaging of magnetic nanostructures as it does not rely on the magnetic dipole interaction, as in conventional high-resolution scanning magnetic force microscopy where the sample magnetization can be affected by the stray-field of the scanning magnetic tip. 2) It represents an approach towards thermal and electric field nanometrology. 3) The contrast mechanism itself may be turned into a novel nano-spectroscopic tool for thin organic layers, forming a hybrid material with a well characterized magnetic substrate. Illustrative examples for the three directions above will be presented.

Resume : The physical and chemical analysis of aerosols using reliable and physically traceable methods is of importance for a thorough investigation of airborne particluate matter in order to support a better understanding of their origin and their impact on health and climate effects. Within the AEROMET [1] project the aim of PTB's X-ray spectrometry group is to develop and establish traceable and reliable X-ray methods to measure the elemental mass deposition per unit area and the elemental composition of particulate matter supported by a flat substrate. The approach used does not require any reference material or specific sample preparation. During field campaign in Budapest, Hungary, and Cassion, Italy, airborne particles were sampled using two different cascade impactors and deposited on substrates suitable for TXRF analysis. A selection of the samples collected and monitored during the field campaigns has been reinvestigated using reference-free X-ray spectrometry with the aim to cross-validate results from mobile TXRF instrumentation used on-site, respectively of thresholds of mass deposition where validation by means of grazing incidence X-ray fluorescence is mandatory. Validated quantification data is highly relevant for defining appropriate legislation and measures for health and climate protection and for supporting their enforcement and monitoring.

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 BCP 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, a 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 is complemented with the TEM and STEM 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 : Health effects caused by particulate air pollution are of high concern. Although the number concentration can be determined routinely by scanning mobility particle sizers, the toxicity of particles depends on their elemental composition and chemical speciation. Total-reflection X-ray fluorescence (TXRF) and near-edge X-ray absorption fine structure (NEXAFS) spectrometry are promising techniques for this task. Size fractionated aerosol samples were collected in Budapest (Hungary) and Cassino (Italy) using a cascade impactor on Si wafers in the size range of 70 nm to 600 nm. The effect of particle load on TXRF quantification and NEXAFS speciation of carbon and nitrogen was tested at the synchrotron radiation facility BESSY II (Berlin, Germany) in the soft X-ray regime. It was found that the X-ray standing wave field is disturbed for high particulate loads requiring corrections for the quantification. NEXAFS results indicated the presence of organic carbon besides the dominating elemental carbon at both sites. Absorption effects are important for samples which are highly loaded with soot and organic particles. Nitrogen was found as ammonium and organic-bound, however radiation damage has to be carefully considered. This work was supported by European Structural and Investment Funds jointly financed by the European Commission and the Hungarian Government through grant no. VEKOP-2.3.2-16-2016-00011 and by the EMPIR initiative of the European Union's Horizon 2020 program, through grant agreement 19ENV08 AEROMET II.

Resume : Over the past decade, the rapid development of information and communication technologies opened new horizons that challenge the state of art of nanoelectronics. In this framework, memristive devices relying on the resistive switching mechanism have recently gained tremendous interest not only in the scientific community but also in the semiconductor industry as building blocks for hardware implementation of in-memory computing architectures beyond ?von Neumann? [1], sensors, low power and as well metrological applications as a standard of resistance by exploiting quantized conductance effects [2]. While these novel materials and devices for nanoelectronics indeed offer many potential benefits, they also bring challenges for testing and characterization. As an emerging technology, memristive devices lack standardization and sufficient level of knowledge on the device fundamental physics underpinning its technology, hindering their further development. Understanding and controlling resistive switching behavior at the nanoscale is therefore highly challenging and high throughput metrology is urgently required. Here, we report on the state-of-the-art nanoelectrical and structural, morphological and electrical nanodimensional characterization techniques for studying memristive cells including scanning probe microscopy techniques and transmission electron microscopy for characterization of nanoscale conductive filaments being an essential component of memristive device functionalities [3-5]. Metrological challenges in establishing a quantification of chemical, structural and ionic/electronic properties of memristive cells will be discussed together with advancement in metrological characterization techniques to meet the requirements needed for the investigation of resistive switching phenomena at the nanoscale. These challenges can be overcome only by developing combined metrological techniques and advanced data analytics, that are also identified as the main challenges for the development of next-generation electronic devices according to the International Roadmap for Devices and Systems (IRDS) [6]. References [1] Wang, Zhongrui, et al. "Resistive switching materials for information processing." Nature Reviews Materials (2020): 1-23. [2] Milano, Gianluca, et al. "Memristive Devices for Quantum Metrology." Advanced Quantum Technologies 3.5 (2020): 2000009. [3] Celano, Umberto, et al. "Three-dimensional observation of the conductive filament in nanoscaled resistive memory devices." Nano letters 14.5 (2014): 2401-2406. [4] Orji, Ndubuisi G., et al. "Metrology for the next generation of semiconductor devices." Nature electronics 1.10 (2018): 532-547. [5] Yang, Yuchao, et al. "Electrochemical dynamics of nanoscale metallic inclusions in dielectrics." Nature communications 5.1 (2014): 1-9. [6] International Technology Roadmap for Semiconductors (IRDS), Metrology, 2020 Edition, available online at: https://irds.ieee.org/editions/2020

Resume : The ALTECH symposium organizers will announce the winners of the Graduate Student Awards and of the Best Poster Awards from ALETCH2021 and provide a balance of the achievements of the conference and technical discussions.