Thin films ofβ-W have attracted much attention due to their fascinating properties for spintronic and magnetic random-access memory but their thermal behavior has still not been well understood. Here we have performed a systematic investigation of their thermal stability and phase transformation behavior using x-ray diffraction, x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), and thermal desorption spectroscopy (TDS). Our results reveal the formation ofβ-W films, which irreversibly transform into theαphase upon heating above 200 °C. XPS measurements indicate the presence of approximately 12 at.% oxygen in theβphase, decreasing to a few percent after annealing up to 500 °C. Complementary TDS, XPS, and SIMS analyses provide quantitative insights into compositional and structural changes during heat treatment, while XPS elucidates the electronic structure, consistent with ourab initiodensity functional theory calculations and molecular dynamics simulations. Theoretical studies reveal that theαphase is energetically more stable at low oxygen concentrations of at least up to ∼10 at.%, corroborating experimentally observedβtoαphase transformation by oxygen desorption.

In this work, we demonstrate device fabrication and characterization of ultrawide bandgap (UWBG) β-(AlxGa1−x)2O3 channel metal–semiconductor field-effect transistors (MESFETs) with Si-implanted source/drain contacts. Films of Si-doped β-(AlxGa1−x)2O3 and unintentionally doped (UID) β-Ga2O3 were grown on an Fe-doped (010) β-Ga2O3 substrate using close-injection showerhead metal–organic chemical vapor deposition (CIS-MOCVD). The Al concentration (x) of the β-(AlxGa1−x)2O3 film was estimated to be ≈21% using x-ray diffraction (XRD), and the Si doping concentration of the n-type β-(Al0.21Ga0.79)2O3 film was measured to be 2 × 1018 cm−3 using secondary ion mass spectroscopy (SIMS). Both gate-recessed and non-recessed MESFET structures were fabricated and had on/off ratios of ≈105. The gate-recessed MESFETs had a lower saturation drain current (15 mA/mm) than the non-recessed structures (26 mA/mm), but they also had a slightly lower off-state leakage current. The gate-recessed structures also enabled better modulation of the channel conductivity, which led to a positive threshold voltage shift of +8V compared with the non-recessed structures. The maximum breakdown voltages of 730 and 858 V were measured for the gate-recessed and non-recessed MESFETs, respectively. Because the thermal conductivity of the disordered alloy β-(Al0.21Ga0.79)2O3 channel is expected to be much lower than β-Ga2O3, thermoreflectance imaging was used to assess the device-level thermal performance. At a DC power density of 0.58 W/mm (VGS = 0 V), an area-averaged gate temperature rise of 54 K was measured. This work demonstrates the potential of leveraging the large-area, low-cost, high-quality β-Ga2O3 substrate platform to develop next-generation power electronics using UWBG β-(AlxGa1−x)2O3 as the active semiconductor.

To realize a chemical diffusion experiment for simple quantitative analysis of one-dimensional diffusion profiles requires the fabrication of a planar and chemically sharp interface between two phases, one serving as the diffusion source and the other as the material to be studied. We demonstrate a thin film source on top of single crystals or epitaxial films for the example of cobalt (II) oxide (CoO) grown on top of SrTiO3 (STO) by ion beam sputtering. After deposition at room temperature, a nearly single-crystalline epitaxial film with a flat and chemically sharp interface is present. Diffusion annealing leads to a partial formation of the Co3O4 phase. We report the conditions where compact and stable CoO layers with flat interface are maintained, serving as a constant source for Co diffusion. Exemplarily, the formation of a Co-diffusion profile is studied by using three different methods: energy dispersive X-ray spectroscopy in a transmission electron microscope, atom probe tomography, and time-of-flight secondary ion mass spectroscopy. The origin of differences in the diffusion constant probed on different sample scales is discussed.

We present a custom sample holder system (SHS) enabling high-fidelity reflectance and transmittance ([R, T]) measurements of small (3-7mm) diamond samples using dual-beam spectrophotometry. Through precision alignment, standard reference material-based correction strategies, and aperture-induced distortion cancellation, the SHS achieves sub-percent absolute photometric accuracy, allowing direct inversion of [R, T] for optical constants [n, k] via a Newton-Raphson (N-R) method. This process eliminates reliance on curve-fitting, instead using branch topology-physical (p-) and mathematical (m-) branch crossings-to extract thickness, roughness, and vertical non-uniformity from fringe behavior. Applied to boron-doped diamond (BDD) homoepitaxial films, the method reduces thickness variance by over 3× compared to mass-gain measurements and reveals carrier density gradients in thin layers consistent with secondary ion mass spectroscopy (SIMS). Notably, ripple-like discontinuities in [n, k]-often dismissed as artifacts-are shown to encode real growth physics. This enables optical retrieval of effective hole mass (∼0.48m0), carrier lifetime, and depth-dependent doping profiles non-destructively and with nanoscale sensitivity. Beyond diamond, this approach reframes spectrophotometry not as a passive measurement but as an epistemic filter: a falsification engine that tests the adequacy of optical models. Inversion-aware metrology thus enables new modes of structural verification, diagnostic clarity, and growth-process insight across small-scale and high-optical density material systems.

Earth-abundant zinc phosphide (Zn3P2) holds great promise as a photovoltaic absorber for thin-film applications, owing to its direct bandgap of ∼1.5 eV and its high absorption coefficient in the visible spectrum. Nonetheless, questions remain about the material’s stability in atmospheric environments, given its tendency to react with surrounding water vapor and oxygen. This work presents a comprehensive long-term study to understand how environmental exposure impacts high-quality, monocrystalline epitaxial zinc phosphide. Through a combination of various experimental techniques, such as ellipsometry, Raman spectroscopy, x-ray diffraction measurements, scanning transmission electron microscopy, energy dispersive x-ray spectroscopy, secondary ion mass spectroscopy, and x-ray photoelectron spectroscopy, we reveal that exposure to the atmosphere causes substantial oxidation of the thin film surface, penetrating several tens of nanometers into the bulk material. Finally, we show that degradation can be effectively prevented by applying a thin dielectric layer, such as Si3N4, or by simply storing the unprotected thin films under vacuum. These findings provide valuable guidelines for the proper handling of the material prior to device fabrication.

Silane-aniline coupling agents were employed to attach polyaniline emeraldine salt (PAni-ES) to cotton fabrics. The cellulose fibers of the cotton fabric were functionalized with silane-aniline molecules using a simple soaking technique. Oxidative polymerization was carried out to form polyaniline molecules from the attached aniline groups. The structural characteristics of the PAni-ES functionalized cotton were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS). FTIR spectra revealed peaks corresponding to the polyaniline structure, suggesting successful attachment. ToF-SIMS showed prominent signals (~10-2) for SiC2H5O+ (73.02 u) and Si3C4HN+ (146.91 u). This indicates strong bonding between the silane-aniline molecules and the polyaniline. The functionalized PAni-ES cotton samples exhibited enhanced antimicrobial properties against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative), demonstrating the effectiveness of the functionalization approach.

The composition, optical and luminescent properties of SiOx:Sm films prepared by vacuum thermal evaporation of a powder mixture of SiO + 1 wt.% Sm have been studied. The study of elemental profiles by time-of-flight secondary ion mass spectroscopy revealed an almost uniform depth distribution of the major elements (Si and O, tracked by presence of Si+, Si2+, O+ and SiO+ ions) as well as Sm (tracked by presence of Sm+ and SmO+ ions). Infrared absorptance spectra (A = 1 – R – T) showed a greater microstructural heterogeneity of the SiOx matrix in the studied films as compared to undoped SiOx films obtained in a similar deposition regime. Further heat treatment in vacuum at 500…700 °C increases the heterogeneity degree of the samples. The optical band gap values of the SiOx:Sm films of 1.5 eV before and 1.77 eV after annealing at 600 °C, determined by the Tauc method correlate well with the literature data for amorphous silicon and Si nanoinclusions in SiO2 matrix, respectively. Measurements of photoluminescence spectra and their analysis have shown that doping of SiOx films with samarium stimulates their decomposition, and heat treatments at temperatures 600 °C form Si nanoparticles in an oxide matrix that exhibit a quantum-size effect.

High-purity single-crystal wide-bandgap semiconductor cubic silicon carbide (3C–SiC) has the second-highest thermal conductivity among wafer-scale crystals (after diamond), making it ideal for thermal management in electronic devices. However, doping—essential for electrical property tuning—may significantly affect its thermal conductivity. While numerous theoretical studies exist, experimental data remain limited. In this work, the thermal conductivity of heavily nitrogen-doped 3C–SiC single crystals grown via the top-seeded solution growth method is measured by time-domain thermoreflectance. The results show a significant reduction (up to 30%) in thermal conductivity at nitrogen doping concentrations around 2 × 1020 cm−3. The doping concentration and distribution are investigated using secondary ion mass spectroscopy and atom probe tomography, revealing an atomic-scale uniform nitrogen distribution. Experimental results show a lower thermal conductivity reduction than previous density functional theory predictions, indicating weaker phonon–electron scattering than expected. Large-area thermal conductivity measurement and mapping reveal spatially uniform thermal conductivity in 3C–SiC at the micro-to-macroscale, emphasizing its practical utility and general high quality. These findings shed light on understanding the doping effects on thermal transport in semiconductors and support further exploration of 3C–SiC for electronics thermal management.

Resistive switching behavior in Cobalt- and Iron based molecular complexes with 2-phenyl azopyridine ligand has been explored in metal-insulator-metal (MIM) structures. While the devices exhibit switching between high-resistance and low-resistance states under an applied electric field, our findings indicate that this behavior is not solely governed by the intrinsic properties of the complexes in itself. Instead, extrinsic factors such as device architecture play a significant role in the observed switching behavior in these types of complexes. Time-of flight secondary ion mass spectroscopy (TOF-SIMS) spectroscopic analyses combined surface profilometry measurements and electrical characterizations suggest that the mechanism involves redox-driven charge trapping/detrapping or filamentary conduction, but the lack of consistency and reproducibility limits its practical applicability. These results highlight the challenges in using transition metal-based complexes for resistive memory applications including hardware based neuromorphic computing and suggest that their suitability for such applications could be limited.

Solid-electrolyte interphase (SEI) is the critical component in all advanced battery chemistries, whose ionic transport and electron leakage behaviors remain least understood among all battery components. Here, using unique in situ liquid secondary ion mass spectroscopy on isotope-labeled SEI, assisted by cryogenic transmission electron microscopy and constrained ab initio molecular dynamics simulation, we answer the question regarding the Li+ transport mechanism across SEI and quantitatively determine the Li+ mobility therein. We unequivocally unveil that Li+ transport in SEI mainly follows a mechanism of successive displacement. We further reveal that in accordance with the spatial dependence of SEI structure across the thickness, the apparent Li+ self-diffusivity continuously drops from the SEI-electrolyte side to the SEI-electrode side (6.7 × 10-19 m2/s to 1.0 × 10-20 m2/s), setting a quantitative gauging of both ionic transport behavior of the SEI layer against the underlying electrode and the rate-limiting step of battery operation. This direct study on Li+ kinetics in SEI fills part of the decade-long knowledge gap about the most important component in advanced batteries and provides more precise guidelines for the tailoring of interphasial chemistries for future battery chemistries.

Hydrolytic and enzymatic degradation of linear segmented polyurethanes with differing compositions were studied by atomic force microscopy and time-of-flight secondary ion mass spectroscopy. Poly (ester urethane urea)s (PEUUs) with two different molecular ratios of polycaprolactone diol (PCL) soft segments and L-lysine diisocyanate/hydrazine hard segments were exposed to aqueous conditions (water or phosphate buffered saline), and the changes in their surface chemistry and morphology were studied. It was found that polymer surface roughness in aqueous conditions is significantly affected by its bulk composition. After soaking in an aqueous buffer solution, the surface of PEUU with higher PCL concentration became significantly rougher compared to PEUU with lower PCL concentration. This surface roughening can be attributed to PCL lost from the surface during hydrolytic degradation. Despite the surface roughness changes, the rate of the hydrolytic degradation of PEUUs was found to be independent of bulk polymer composition. Enzymatic degradation of a linear segmented PEUU containing an oligopeptide segment [poly(peptide urethane urea) (PPUU)] in a collagenase solution was also investigated. The PPUU oligopeptide segment contained proline, hydroxyproline, and glycine amino acids. In a collagenase solution, the PPUU polymer exhibited a significantly higher degradation rate and surface roughness compared to a PEUU polymer that did not contain the oligopeptide segment.

Low-temperature NH3-SCO over CuOx/Al2O3 enhanced by precursor-derived Cl-bonded Cu species

Silicon nitride (SiNx) thin films play a crucial role in the semiconductor industry due to their controllable properties, which make them suitable for various applications. In this study, SiNx films, with varying composition ratios (x=[N]/[Si]), were fabricated under different conditions using plasma-enhanced chemical vapor deposition (PECVD). The composition significantly affects the structural, optical and electrical properties of the films. We investigate the characteristics that depend on the stoichiometric composition of amorphous hydrogenated SiNx films (ranging from N-rich to Si-rich) through techniques such as X-ray photoelectron spectroscopy (XPS), electron microprobe microscopy (EMP), ellipsometry, Fourier transform infrared spectroscopy (FTIR), secondary ion mass spectroscopy (SIMS), and high-voltage broadband dielectric spectroscopy (HVBDS). Key parameters, including refractive index, bonding structure, permittivity, loss factor and AC conductivity are analyzed and discussed in relation to the x=[N]/[Si] ratio. The presence of hydrogen in PECVD SiNx is also examined with Si-H and N-H bonds varying based on the x ratio. These variations influence the film electrical conduction properties with low-frequency HVBDS accurately identifying the structural transitions between N-rich and Si-rich compositions. These results show the key role of the Si-N bonding and hydrogenation (mainly through Si-H bonding) in controlling nonlinear conduction of SiNx films.

Abstract Metal−organic frameworks (MOFs) provide breakthroughs in nanophotonics with unique advantages in integrating white light emission with fluorescence and phosphorescence. With their porous properties and confined capacities, MOFs accommodate luminescent guests (LG), resulting in LG@MOFs systems. Encapsulation of silicon quantum dots (Si QDs) and europium (Eu) with Zeolitic Imidazolate Framework‐8 (ZIF‐8) (Si QDs@xEZIF‐8; x = 0.25, 0.5, and 0.75) enables multiple luminescence centers with a high photoluminescence quantum yield (PLQY) of 6.71% while suppressing the aggregation‐caused quenching (ACQ). The luminescence effect is enhanced by applying various pressures ranging from 0.074 to 0.52 GPa in SiQDs@0.5EZIF‐8 with a long emission of 2.04 ms at 0.52 GPa applied pressure, significantly enhancing solid‐state white light emission with a correlated color temperature (CCT) of 8482 K. In ambient conditions, the as synthesized material retains ≈75% of its initial intensity over 13 days and ≈78% under UV exposure for 75 minutes. The pressure‐induced white light emission from SiQDs@0.5EZIF‐8 exhibits excellent photostability which retaining over 88% of its initial intensity under continuous 397 nm excitation for 120 minutes without further degradation, significantly improving resistance to photodegradation. The confocal fluorescence microscopy (CFM) utilized to confirm the encapsulation technique, and time‐of‐flight secondary ion mass spectroscopy (TOF‐SIMS) provided the surface analysis of the pressure applied to SiQDs@0.5EZIF‐8.

Various reports on phosphorus‐doped diamond growth present a prominent variation in the doping profile and the doping gradient at the substrate/epilayer interface. This warrants a closer investigation of the growth process, in particular, the gas chemistry via residual gas analysis (RGA) to determine whether a doping indicator exists that would allow a real‐time control of the phosphorus incorporation. Phosphorus‐doped diamond films are prepared by plasma‐enhanced chemical vapor deposition utilizing a 200 ppm trimethylphosphine in hydrogen gas mixture. The phosphorus‐doped diamond growth is characterized by in situ RGA, which identifies a diatomic radical (PH) formed in the hydrogen plasma. A rapid analysis response is achieved through an engineered differentially pumped component. Secondary ion mass spectroscopy (SIMS) is employed to evaluate the phosphorus incorporation in the doped diamond epilayers. The SIMS‐derived phosphorus doping profile is correlated to the RGA‐measured PH concentration. For an epilayer grown on a (111) chemical vapor deposition‐type IIa substrate with moderate miscut a significant phosphorus incorporation of 4.5 × 10 19 cm −3 is measured with an incorporation efficiency of about 10%. A doping model is derived that utilizes RGA for dominant growth and doping species and under consideration of various growth modes.

This article provides an overview of laser color marking of titanium based on annealing. The mechanism of the formation of oxide layers under the influence of laser radiation and the properties of these layers are discussed. Then, the most commonly used lasers for the creation of color oxide layers are listed. The results of the change in morphology and surface roughness are shown. After that, an overview of the surface composition analysis by means of x-ray photoelectron spectroscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, and Raman techniques is presented. The layer thicknesses estimated by the ellipsometric, secondary ion mass spectroscopy, and transmission electron microscopy methods are given. The influence of the process parameters on the produced oxides is shown. The following sections present the results of corrosion, friction, and wear resistance. This work also summarizes the results of the research on the influence of the gas environment, wettability, and the ability to remove oxides. Finally, a section is devoted to explain about further work required in order to use this method commercially in the future.

Herein, a systematic study is reported on the synthesis and characterization of single‐phase rhenium nitride (ReN) thin films grown using a reactive dc magnetron sputtering (R‐dcMS). ReN thin films are expected to be superhard (bulk modulus ≈ 400 GPa) and superconducting ( T c ≈ 5 K). Since the formation enthalpy of ReN ≈ –0.14 eV is comparatively high, a stringent control of growth parameters such as partial N 2 gas flow () and growth temperature ( T s ) is necessary to achieve an impurity free and single‐phase ReN. The and the T s are systematically varied during the R‐dcMS process to find the optimal conditions for growth of ReN phase. Resulting samples are studied using X‐ray reflectivity to determine the deposition rate, density, and roughness. The crystal structure and depth profile of ReN thin films have been probed using X‐ray diffraction and secondary ion mass spectroscopy. The electronic structure is studied using hard X‐ray photoelectron spectroscopy and N K‐edge X‐ray absorption near edge structure. The superconducting transition temperature ( T c ) is found to be 3.3 K from the zero field electrical resistivity measurement. The present work constructs a phase diagram to identify the optimal conditions for forming single‐phase ReN films.

The solid electrolyte interphase (SEI) can significantly improve the low Coulombic Efficiency and poor cycling performance of anode-free Li metal batteries (AFLMBs). However, the sensitive nature of the SEI layer, its restricted environment, and the complex working conditions of the battery system complicate its investigation under operational conditions. We apply operando odd random phase electrochemical impedance spectroscopy (ORP-EIS) to monitor the formation of the SEI layer for AFLMBs. Operando ORP-EIS is measured for the Cu substrate during cathodic polarization from the open-circuit voltage to −0.4 V vs Li/Li+ in 1 M LiPF6 in EC/DMC (1:1 v/v), providing qualitative information regarding the reaction resistances during SEI formation. To further study the properties of the SEI layer and support the operando ORP-EIS findings, we employ surface analysis techniques, including field-emission gun scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). We observe that the formation of different compounds on the anode (negative electrode) as a function of applied charging potential influences the SEI properties. This nondestructive operando ORP-EIS technique provides an opportunity to obtain realistic information about the SEI layer and measure charge transfer resistance of occurring reactions. This technique facilitates the development of AFLMBs.

The introduction of NaOH catalysts at an SiO2/SiO2 hydrophilic bonding interface is investigated. Combining bonding energy measurements, interface hard x-ray reflectometry, transmission electron microscopy, and time of flight secondary ion mass spectroscopy, the change of interface morphology, and composition as a function of surface preparation is evidenced. The hydroxide catalyzed interface shows the formation of interface nanoclusters, associated with the low temperature interface sealing. A reference interface (bonded without a catalyst) is sharper. These contrasting behaviors highlight the issue of water management at the interface and the balance between interface sealing and water out-diffusion. The additional impact of oxide thickness in interfacial water management is further investigated. Finally, the catalytic interface sealing is compared with other surface preparations that achieve high bonding energies at low temperatures.

Abstract The objective of the present study is to investigate the hardening behavior, superelastic recovery, and structural properties of NiTi Shape Memory Alloy (SMA) after 10 MeV high-energy Fe+ ion irradiation to damage levels of 1.2 and 6.0 d.p.a (displacements per atom). According to Stopping and Range of Ions in Matter (SRIM) calculations, Secondary Ion Mass Spectroscopy (SIMS) analysis, and Transmission Electron Microscopy (TEM) imaging, a 3-micron irradiation layer was obtained with an amorphous structure; the maximum values of damage and Fe+ ion concentration occurred at 2.4 and 2.7 microns, respectively. The mechanical response was characterized in two-direction nanoindentation tests: parallel and perpendicular to the ion beam direction. Cross-sectional nanoindentation indicates that the maximum hardening corresponds to the maximum of the Fe+ ion concentration; the maximum hardness was found at 2.7 microns for both d.p.a. levels. The changes in superelastic properties were achieved in the amorphous layer that suppressed the B2-B19′ phase transformation at a sub-micron scale. We show that cross-sectional nanoindentation is an appropriate method for determining the subtle micromechanical property changes in near-surface regions. It also allows the material and structural properties at a selected point in the non-homogeneous irradiated layer to be correlated with the local level of irradiation damage or ion concentration. This is very important in the development of SMAs and their applications in nuclear technologies.