Patterned and multilayer materials used in advanced technologies exhibit complex three-dimensional compositional architectures in which buried interfaces and elemental gradients critically influence performance. However, most non-destructive analytical techniques remain largely surface-sensitive, limiting access to subsurface information in opaque systems. In this work, we present a novel framework for non-destructive three-dimensional elemental characterization based on the integration of artificial neural networks with ion beam analysis techniques, namely, Particle-Induced X-ray Emission (PIXE) and Elastic Backscattering Spectrometry (EBS). The proposed approach enables the reconstruction of depth-resolved 3D elemental distributions by combining complementary spectral information with data-driven analysis. The methodology is demonstrated on a GaSb thermophotovoltaic device featuring multilayer metallic contacts, where the elemental distribution beneath thick gold layers is revealed for the first time. The neural network approach overcomes limitations associated with low counting statistics in pixel-resolved spectra, enhancing sensitivity and enabling reliable classification of compositional features. The fusion of PIXE-derived lateral information with EBS-based depth profiling enables full three-dimensional visualization and quantitative and qualitative mapping of elemental distributions. Beyond the specific case study presented, this approach provides a general and scalable strategy for 3D compositional analysis of complex materials, including systems containing both heavy and light elements. The results highlight the potential of combining advanced data-driven methods with ion beam techniques to expand the capabilities of non-destructive characterization, with broad applicability in energy, electronics, and functional materials.

This study reports on the influence of nanostructure design on the corrosion behaviour of titanium nitride (TiN) thin films, prepared by DC reactive magnetron sputtering, using the Glancing Angle Deposition (GLAD) technique. The primary objective was to explore how modifying the deposition geometry affects the growth design and surface features of TiN films (keeping roughly constant the N/Ti ratio) and compare these effects with those produced by changing the chemical composition within the same thin film system (N/Ti increasing ratios). For this, two groups of samples were prepared: Group 1 - the samples were prepared in the conventional geometry (normal growth) with varied nitrogen content (stoichiometric and non-stoichiometric films) and; Group 2 - the samples were prepared with modified growth geometries (inclined and zigzag, with increasing incidence angles), keeping an almost unchanged stoichiometry. The results revealed increased surface porosity and roughness for Group 2 films compared to Group 1, demonstrating that deposition geometry can affect more significantly the surface characteristics than the composition variations. Corrosion studies indicated that the films prepared within Group 2, despite having higher porosity, showed a more stable open circuit potential (OCP) and nobler values than the reference close-stoichiometric TiN 0.92 film (reference sample) from Group 1. However, potentiodynamic polarization curves suggested higher corrosion kinetics for Group 2 films, most likely due to their increased surface heterogeneities. Electrochemical impedance spectroscopy (EIS) confirmed these findings, showing lower corrosion resistance for films prepared with inclined and zigzag geometries, if compared to the films prepared in conventional geometry (Group 1 samples). This study advances the current state of the art on this film's responses, by demonstrating that tailoring nanostructure design through deposition geometry offers a promising approach to optimize the corrosion behaviour of TiNx without the need to change its composition.

This study aimed to investigate the degradation of dry biopotential electrodes using the anodic stripping voltammetry (ASV) technique. The electrodes were based on Ti-Cu thin films deposited on different polymeric substrates (polyurethane, polylactic acid, and cellulose) by Direct Current (DC) magnetron sputtering. TiCu0.34 thin films (chemical composition of 25.4 at.% Cu and 74.6 at.% Ti) were prepared by sputtering a composite Ti target. For comparison purposes, a Cu-pure thin film was prepared under the same conditions and used as a reference. Both films exhibited dense microstructures with differences in surface topography and crystalline structure. The degradation process involved immersing TiCu0.34 and Cu-pure thin films in artificial sweat (prepared following the ISO standard 3160-2) for different durations (1 h, 4 h, 24 h, 168 h, and 240 h). ASV was the technique selected to quantify the amount of Cu(II) released by the electrodes immersed in the sweat solution. The optimal analysis conditions were set for 120 s and −1.0 V for time deposition and potential deposition, respectively, with a quantification limit of 0.050 ppm and a detection limit of 0.016 ppm. The results showed that TiCu0.34 electrodes on polyurethane substrates were significantly more reliable over time compared to Cu-pure electrodes. After 240 h of immersion, the TiCu0.34 electrodes released a maximum of 0.06 ppm Cu, while Cu-pure electrodes released 16 ppm. The results showed the significant impact of the substrate on the electrode’s longevity, with cellulose bases performing poorly. TiCu0.34 thin films on cellulose released 1.15 µg/cm2 of copper after 240 h, compared to 1.12 mg/cm2 from Cu-pure films deposited on the same substrate. Optical microscopy revealed that electrodes based on polylactic acid substrates were more prone to corrosion over time, whereas TiCu thin-film metallic glass-like structures on PU substrates showed extended lifespan. This study underscored the importance of assessing the degradation of dry biopotential electrodes for e-health applications, contributing to developing more durable and reliable sensing devices. While the study simulated real-world conditions using artificial sweat, it did not involve in vivo measurements.

Over the last few years, there has been increasing interest in the use of amorphous carbon thin films with low secondary electron yield (SEY) to mitigate electron multipacting in particle accelerators and RF devices. Previous works found that the SEY increases with the amount of incorporated hydrogen and correlates with the Tauc gap. In this work, we analyse films produced by magnetron sputtering with different contents of hydrogen and deuterium incorporated via the target poisoning and sputtering of CxDy molecules. XPS was implemented to estimate the phase composition of the films. The maximal SEY was found to decrease linearly with the fraction of the graphitic phase in the films. These results are supported by Raman scattering and UPS measurements. The graphitic phase decreases almost linearly for hydrogen and deuterium concentrations between 12% and 46% (at.), but abruptly decreases when the concentration reaches 53%. This vanishing of the graphitic phase is accompanied by a strong increase of SEY and the Tauc gap. These results suggest that the SEY is not dictated directly by the concentration of H/D, but by the fraction of the graphitic phase in the film. The results are supported by an original model used to calculate the SEY of films consisting of a mixture of graphitic and polymeric phases.

This study investigated the impact of the nanostructure design of titanium nitride (TiNx) thin films on their optical, electrical and thermal properties. The growth designs of the films were tailored using conventional sputtering (series 1) and GLancing Angle Deposition (GLAD) geometries (series 2 and 3). The results showed the potential to modify the properties of thin films by adjusting their nanostructure design, rather than changing their composition. TiNx thin films prepared by GLAD, revealed wider and more significant variations in optical and electrical properties, while the thermal properties seemed to be more affected by the structural changes promoted by the N content in the films. GLAD geometries resulted in the reduction of the film's reflectivity, and colour coordinates, as well as an increase in the electrical resistivity. The thermal parameters of effusivity ratio and diffusivity were reduced as the N/Ti ratio increased.

Thermoelectric transparent ZnO:Sb thin films were deposited by magnetron sputtering, with Sb content varying between 2 and 14 at%. As evidenced by X-ray diffraction analysis, the films crystallize in the ZnO wurtzite structure for lower levels of Sb-doping, developing a degree of amorphization for higher levels of Sb-doping. Temperature-dependent (10-300 K) X-ray absorption spectroscopy studies of the produced thin films were performed at the Zn and Sb K-edges to shed light on the influence of Sb doping on the local atomic structure and disorder in the ZnO:Sb thin films. The analysis of the Zn K-edge EXAFS spectra by the reverse Monte Carlo method allowed to extract detailed and accurate structural information in terms of the radial and bond angle distribution functions. The obtained results suggest that the introduction of antimony to the ZnO matrix promotes static disorder, which leads to partial amorphization with very small crystallites (-3 nm) for large (12-14 at%) Sb content. Rutherford backscattering spectrometry (RBS) experiments en-abled the determination of the in-depth atomic composition profiles of the films. The film composition at the surfaces determined by X-ray photoelectron spectroscopy (XPS) matches that of the bulk determined by RBS, except for higher Sb-doping in ZnO films, where the concentration of oxygen determined by XPS is smaller near the surface, possibly due to the formation of oxygen vacancies that lead to an increase in electrical conductivity. Traces of Sb-Sb metal bonds were found by XPS for the sample with the highest level of Sb-doping. Time-of-flight secondary ion mass spectrometry obtained an Sb/Zn ratio that follows that of the film bulk determined by RBS, although Sb is not always homogeneous, with samples with smaller Sb content (2 and 4 at% of Sb) showing a larger Sb content closer to the film/substrate interface. From the optical transmittance and reflectance curves, it was determined that the films with the lower amount of Sb doping have larger optical band-gaps, in the range of 2.9-3.2 eV, while the partially amor-phous films with higher Sb content have smaller band-gaps in the range of 1.6-2.1 eV. Albeit the short-range crystalline order (-3 nm), the film with 12 at% of Sb has the highest absolute Seebeck coefficient (-56 mu V/K) and a corresponding thermoelectric power factor of-0.2 mu W center dot K-2 center dot m-1.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Amorphous carbon (a-C) films, having low secondary electron yield (SEY), are used at CERN to suppress electron multipacting in the beam pipes of particle accelerators. It was already demonstrated that hydrogen impurities increase the SEY of a-C films. In this work, a systematic characterization of a set of a-C coatings, deliberately contaminated by deuterium during the magnetron sputtering deposition, by scanning electron microscopy, ion beam analysis, secondary ion mass spectrometry, and optical absorption spectroscopy was performed to establish a correlation between the hydrogen content and the secondary electron emission properties. In parallel, the mechanisms of contamination were also investigated. Adding deuterium allows resolving the contributions of intentional and natural contamination. The results enabled us to quantify the relative deuterium/hydrogen (D/H) amounts and relate them with the maximum SEY (SEYmax). The first step of incorporation appears to be formation of D/H atoms in the discharge. An increase in both the flux of deposited carbon atoms and the discharge current with a D2 fraction in the gas discharge can be explained by target poisoning with deuterium species followed by etching of CxDy clusters, mainly by physical sputtering. For overall relative D/H amounts between 11% and 47% in the discharge gas, the SEYmax increases almost linearly from 0.99 to 1.38. An abrupt growth of SEYmax from 1.38 to 2.12 takes place in the narrow range of D/H relative content of 47%–54%, for which the nature of the deposited films changes to a polymer-like layer.

This work reports on the development of nanoplasmonic thin films consisting of Au, Ag, or Au-Ag nanoparticles dispersed in a TiO2 matrix and the optimization of the deposition parameters to tune their optical response. The thin films were produced by reactive DC magnetron sputtering of a Ti target with Au and/or Ag pellets placed on the erosion zone. The thicknesses (50 and 100 nm) of the films, the current density (75 and 100 A/m2) applied to the target (titanium), and the number of pellets placed on its surface were the deposition conditions that were used to tailor the optical (LSPR) response. The total noble metal content varied between 13 and 28 at.% for Au/TiO2 films, between 22 and 30 at.% for Ag/TiO2 films, and 8 to 29 at% for the Au-Ag/TiO2 systems with 1:1, 1:1.5, and 1:2 Au:Ag atomic ratios. After thermal annealing at 400 and 600 °C, LSPR bands were found for all films concerning the Au-TiO2 and Au-Ag/TiO2, while for Ag/TiO2, only for thin films with 28 and 30 at.% of Ag concentration. Refractive index sensitivity (RIS) was evaluated for Au and Au-Ag/TiO2 thin films. It was found that for bimetallic nanoparticles, the sensitivity can increase up to five times when compared to a monometallic nanoplasmonic system. Using Au-Ag/TiO2 thin films can decrease the cost of fabrication of LSPR transducers while improving their sensitivity.

The possibility to tune the elemental composition and structure of binary Me oxynitride-type compounds (Me1Me2ON) could lead to attractive properties for several applications. For this work, tantalum-titanium oxynitride (TaTiON) thin films were deposited by DC reactive magnetron co-sputtering, with a –50 V bias voltage applied to the substrate holder and a constant substrate temperature of 100 °C. To increase or to decrease in a controlled manner, the Ti and Ta content in the co-sputtered films, the Ti and Ta target currents were varied between 0.00 and 1.00 A, in 0.25 A steps, while keeping the sum of the currents applied to the two targets at 1.00 A. The reactive gases flow, consisting of a nitrogen and oxygen gas mixture with a constant N2/O2 ratio (85%/15%), was also kept constant. The single-metal oxynitrides (TaON and TiON) showed a low degree of crystallinity, while all the other co-sputtered films revealed themselves to be essentially amorphous. These two films also exhibited higher adhesion to the metallic substrate. The TaON film showed the highest hardness value (14.8 GPa) and the TiON film a much lower one (8.8 GPa), while the co-sputtered coatings exhibited intermediary values. One of the most interesting findings was the significant increase in the O content when the Ti concentration surpassed the Ta one. This significantly influenced the optical characteristic of the films, but also their electrical properties. The sheet resistivity of the co-sputtered films is strongly dependent on the O/(Ta + Ti) atomic ratio.

In order to establish the variation between results in mass fractions due to software implementation, as measured by the k0-method for INAA, the IAEA has organized a software intercomparison. A complete set of test spectra and associated information was assembled. Efficiency curves, neutron spectrum parameters, correction factors and mass fractions were calculated with the participating programs (k0-IPEN, k0-INRIM, k0-DALAT, k0-IAEA and KayWin) using identical peak areas. In this paper, we report on the observed discrepancies, causes, remedies and future software developments. The test data, as well as intermediate results and observed mass fractions of the certified reference material BCR-320R “channel sediment” are available through the IAEA on request. The variations in concentrations attributed to differences between the programs were initially found to be 5.6 and 7.9%, for certified and uncertified concentrations, respectively. After the certified concentrations had been made available to the participants and they had been allowed to improve their programs, the variations found were 2.7 and 3.4%, respectively. The main identified remaining causes of variation are differences in the procedures used for detector efficiency characterisation and neutron spectrum parameter determination.

In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, this work pretends to attain the maximum sensing response of the thin film system and to demonstrate its potential as a gas sensor. The results show that as Ar plasma treatment time increases, the host CuO matrix is etched while Au nanoparticles are uncovered, which leads to an enhancement of the sensitivity until a certain limit. Above such a time limit for plasma treatment, the CuO bonds are broken, and oxygen is removed from the film’s surface, resulting in a decrease in the gas sensing capabilities. Hence, the importance of the host matrix for the design of the LSPR sensor is also demonstrated. CuO not only provides stability and protection to the Au NPs but also promotes interactions between the thin film’s surface and the tested gases, thereby improving the nanocomposite film’s sensitivity. The optimized sensor sensitivity was estimated at 849 nm/RIU, which demonstrates that the Au-CuO thin films have the potential to be used as an LSPR platform for gas sensors.

This work was focused on the characterization of plasmonic thin films composed of Au-Ag nanoparticles dispersed in a TiO2 dielectric matrix in comparison with the monometallic Au/TiO2 plasmonic system. The thin films were prepared by reactive DC magnetron sputtering, followed by thermal annealing at different temperatures to promote nanoparticles' growth. Thermal treatment from 400 degrees C induced the appearance of Localized Surface Plasmon Resonances (LSPRs) in both Au/TiO2 and Au-Ag/TiO2 thin films. The latter showed a wider LSPR response, due to the broader size distribution of nanoparticles (analyzed by transmission electron microscopy, TEM). Further nanometer-scale chemical analysis allowed to confirm the presence of Au-Ag bimetallic nanoparticles. To thoroughly study the influence of the annealing treatment on the nanoparticles' growth, Au-Ag/TiO2 was also deposited on heating TEM nano-chips for in-situ annealing experiments. The formation of silver aggregates was found in the sample as-deposited, with these precipitates dissolving in the matrix with the increase of annealing temperature up to 200 degrees C. For higher temperatures, nanoparticles' real-time growth was observed, together with the crystallization of the TiO2 matrix above 550 degrees C. Besides, the plasmonic Au-Ag/TiO2 thin films revealed LSPR sensitivity when in contact with different dielectric media, highlighting their potential as refractive index sensors.

This work reports on undoped and Sn-doped indium sulfofluoride thin-films deposited by radio-frequency plasma-enhanced reactive thermal evaporation. The deposition was performed evaporating pure indium or indium-tin alloy in SF6 plasma at substrate temperatures ranging from 373 to 423 K. Rutherford backscattering analysis and secondary-ion mass spectrometry were used to determine the chemical composition of the films. The film characterization includes electrical, optical, and photoconductivity measurements. The resistivity of undoped material varies in a wide range of 1 G Omega-cm to 2 T Omega-cm depending on deposition conditions. Sn doping leads to a decrease in the resistance down to 8 M Omega-cm. The films are highly transparent in the visible-infrared region due to an indirect bandgap of 2.7-3 eV. Moreover, the doped material is highly photosensitive in the blue -UV region. Photoconductivity kinetics under various excitation conditions was also studied. The synthesized material is a promising candidate for a buffer layer in chalcogenide-based solar cells.

Tin sulphide (SnS) thin films have been grown by Chemical Bath Deposition (CBD) and annealed up to 600 degrees C. Non-intentionally doped films show p-type conduction which makes them an ideal partner material for p-n type photovoltaic devices. Most of the films were modestly Ga-doped, but addition of other elements like Fe, Cu, and In was also investigated. We studied essential optoelectronic material parameters like band gap, Urbach tail parameter, and optical absorption using transmission measurements. We found marked differences in the composition of the film surface and of the bulk region. Such complementary results were possible through X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering analysis (RBS), respectively. A tentative model of surface modification and diffusion barrier formation based on thermodynamic arguments is given. Emphasis is put on the study of kinetics of photoinduced carriers after high-power laser pulses by contactless Microwave Transient Reflection (MWTR) analysis. The MWTR signal intensity is increasing strongly upon thermal annealing from 200 to 600 degrees C, reflecting the strongly improved photoactivity.

In this work, we explore the addition of Ti ribbons on the racetrack of a Zr target to prepare Zr-O-N films including Ti, by reactive magnetron sputtering with a mixture of N2 and O2 as reactive gases. This approach is simple and not invasive, it avoids the modification of the target and minimizes its contamination. These films were compared in terms of chemical composition, density, film growth and crystallographic structure with others prepared in identical conditions without Ti ribbons. In addition, the composition and density of the films were correlated with crystallographic references from literature. The color and electrical properties of the films were evaluated as well. It was observed that poisoning of the Zr target is promoted by the increase of the N2 + O2 flow and the reduction of magnetron current, but it is retarded by the introduction of the Ti ribbons. This effect was particularly remarkable at lower target current, since the sputtering is confined in areas nearer to the racetrack, where the Ti ribbons are located. To account for the poisoning of the target and compare it among the different samples, a ‘poisoning parameter’ was defined, using a combination of the chemical composition of the films and the deposition rates. The color and electrical properties of the films correlate surprisingly well with their oxygen-to-metal ratio, while the concentration of N does not seem to play any significant role.

a-SiCN:H thin films were deposited at 150°C by PECVD using silane, methane and ammonia as precursor gases, with a SiH4:H2 dilution of 1:9. RBS and ERDA were used for determining material composition. The concentration of silicon, carbon and nitrogen in the deposited films was correlated with the respective precursor gas concentration and the incorporation yield of each atomic species was determined and related to the molecular bond energies of precursor gases. Chemical bonding type and density determined by FTIR were also related to the chemical composition of the films. Optical transmission was measured to estimate the optical gap (Eop) and refractive index (n) in the transparent region. Stoichiometric a-SiN has the lowest n (1.74) and highest Eop (4.12 eV) while a-Si:H presents the highest n (3.37) and lowest Eop (1.85 eV). A trade-off between the Eop and n is presented to show the applicability of this ternary material in optical devices.

Research reactors contribute to improve the health of people, to combat climate change, to develop the materials that will underpin the technologies of the future, to educate the new generations of professionals in nuclear science and technology and in many other fields, to generate new knowledge for humanity, and to enhance prosperity and development of society. This article describes the most important applications of research reactors worldwide, including production of radioisotopes for medicine and industry, education and training, materials analysis with various techniques and other specialized applications.

Accelerators are behind many major scientific and technological breakthroughs giving a gigantic contribution to unveil the mysteries of matter. This quest continues nowadays using the high-energy machines operating at large research centres like CERN, GANIL and FAIR, among others. Meanwhile most of the small and medium size accelerators running in laboratories located in universities and research institutions around the world begin a new life making available the powerful nuclear-based techniques for multidisciplinary research in several domains. Furthermore, the small and medium size accelerator facilities still play a major role in keeping and providing knowledge in Nuclear Science and training the new generations. The two electrostatic accelerators at Instituto Superior Técnico of the University of Lisbon are devoted to multidisciplinary research as well as education and training students in nuclear-based experimental techniques. The history and work carried out in the laboratory and its role in areas with great societal impact such as materials science, energy, biomedical sciences as well as nuclear experimental physics in support of the large-scale facilities, will be highlighted in the manuscript.

In a new era for digital health, dry electrodes for biopotential measurement enable the monitoring of essential vital functions outside of specialized healthcare centers. In this paper, a new type of nanostructured titanium-based thin film is proposed, revealing improved biopotential sensing performance and overcoming several of the limitations of conventional gel-based electrodes such as reusability, durability, biocompatibility, and comfort. The thin films were deposited on stainless steel (SS) discs and polyurethane (PU) substrates to be used as dry electrodes, for non-invasive monitoring of body surface biopotentials. Four different Ti–Me (Me = Al, Cu, Ag, or Au) metallic binary systems were prepared by magnetron sputtering. The morphology of the resulting Ti–Me systems was found to be dependent on the chemical composition of the films, specifically on the type and amount of Me. The existence of crystalline intermetallic phases or glassy amorphous structures also revealed a strong influence on the morphological features developed by the different systems. The electrodes were tested in an in-vivo study on 20 volunteers during sports activity, allowing study of the application-specific characteristics of the dry electrodes, based on Ti–Me intermetallic thin films, and evaluation of the impact of the electrode–skin impedance on biopotential sensing. The electrode–skin impedance results support the reusability and the high degree of reliability of the Ti–Me dry electrodes. The Ti–Al films revealed the least performance as biopotential electrodes, while the Ti–Au system provided excellent results very close to the Ag/AgCl reference electrodes.