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0D organic metal halide hybrids (OMHHs) have recently emerged as a new generation of scintillation materials, due to their high luminescence quantum efficiency, sensitivity, stability, and cost‐effectiveness. While numerous 0D OMHH scintillators have been developed to date, most of them are based on solution grown single crystals that require time‐consuming synthesis and are limited in size. Here, high‐performance X‐ray scintillators based on facile solution processed 0D OMHH amorphous films are reported for the first time. By reacting triphenyl(9‐phenyl‐9H‐carbazol‐3‐yl) phosphonium bromide (TPPcarzBr) with manganese bromide (MnBr2), 0D (TPPcarz)₂MnBr₄ amorphous films can be prepared via solution processing with mild thermal annealing, which exhibits green photoluminescence with an emission maximum ≈517 nm and a photoluminescence quantum efficiency of ≈87%. The X‐ray scintillation of 0D (TPPcarz)₂MnBr₄ amorphous films is characterized to exhibit a light yield of 44600 photon MeV−1 and an outstanding linearity with a low limit of detection of 32.42 nGyairs−1 over a wide range of X‐ray dose rates. The versatile processability of 0D (TPPcarz)₂MnBr₄ is illustrated with remarkable recyclability, high cost‐effectiveness, and scalability for large‐scale production. By taking advantage of the amorphous nature of newly designed OMHHs, the approach opens up new opportunities for developing high‐performance, solution‐processable scintillators. [ABSTRACT FROM AUTHOR]

Singlet fission (SF), as an effective way to break through the Shockley–Queisser limit, can dramatically improve energy conversion efficiency in solar cell areas. The formation, separation, and relaxation of triplet-pair excitons directly affect the triplet yield, especially triplet-pair separation; thus, how to enhance the triplet-pair separation rate becomes one of the key points to improve SF efficiency; the decay mechanism where the singlet state is converted into two triplet states is significant for the study of the SF mechanism. Herein, we employ ultrafast transient absorption spectroscopy to study the singlet-fission process of nano-amorphous 6, 13-bis(triisopropylsilylethynyl)-Pentacene (TIPS-pentacene) films in a diamond anvil cell (DAC). A kinetics model related to the structural geometric details, as well as an evaluation of the pressure manipulation impacts, is demonstrated based on the experimental results. The results indicate that pressure manipulation enhanced the triplet-pair separation rates of SF-based materials according to their structural micro-environmental improvement when compressed in DAC, while the triplet-exciton transportation lifetime is prolonged. This work shows that pressure may effectively optimize the structural disorder of SF materials, which were found to improve triplet-pair separation efficiency and potentially offer an effective way to further improve SF efficiency. [ABSTRACT FROM AUTHOR]

Singlet fission (SF), as an effective way to break through the Shockley–Queisser limit, can dramatically improve energy conversion efficiency in solar cell areas. The formation, separation, and relaxation of triplet-pair excitons directly affect the triplet yield, especially triplet-pair separation; thus, how to enhance the triplet-pair separation rate becomes one of the key points to improve SF efficiency; the decay mechanism where the singlet state is converted into two triplet states is significant for the study of the SF mechanism. Herein, we employ ultrafast transient absorption spectroscopy to study the singlet-fission process of nano-amorphous 6, 13-bis(triisopropylsilylethynyl)-Pentacene (TIPS-pentacene) films in a diamond anvil cell (DAC). A kinetics model related to the structural geometric details, as well as an evaluation of the pressure manipulation impacts, is demonstrated based on the experimental results. The results indicate that pressure manipulation enhanced the triplet-pair separation rates of SF-based materials according to their structural micro-environmental improvement when compressed in DAC, while the triplet-exciton transportation lifetime is prolonged. This work shows that pressure may effectively optimize the structural disorder of SF materials, which were found to improve triplet-pair separation efficiency and potentially offer an effective way to further improve SF efficiency.

Using Messbauer spectroscopy on 119Sn impurity atoms, it was demonstrated that in amorphous (GeTe)x(Sb2Te3) films (where x = 0.5, 1, 2, 3) tin atoms replace atoms of tetravalent germanium, which forms a tetrahedral system of chemical bonds with atoms in its local environment. In crystalline films, tin replaces divalent six-coordinated germanium in positions 4b of the NaCl-type crystal lattice. [ABSTRACT FROM AUTHOR]

Using Messbauer spectroscopy on 119Sn impurity atoms, it was demonstrated that in amorphous (GeTe)x(Sb2Te3) films (where x = 0.5, 1, 2, 3) tin atoms replace atoms of tetravalent germanium, which forms a tetrahedral system of chemical bonds with atoms in its local environment. In crystalline films, tin replaces divalent six-coordinated germanium in positions 4b of the NaCl-type crystal lattice. [ABSTRACT FROM AUTHOR]

By the method of Mössbauer spectroscopy on the isotope 119Sn, it was shown that tetravalent germanium atoms in amorphous films (GeTe)x(Sb2Te3) (where x = 0.5, 1, 2, 3) form a tetrahedral system of chemical bonds, and in their local environment there are mainly tellurium atoms. In crystalline films (GeTe)x(Sb2Te3) is divalent hexoordinated germanium at positions 4 b of the NaCl type crystal lattice. By the method of Mössbauer spectroscopy on 121Sb and 125Te atoms, it was shown that the amorphization of (GeTe)x(Sb2Te3) films does not change the local environment of antimony and tellurium atoms. [ABSTRACT FROM AUTHOR]

Antimony sulfide (Sb2S3) solar cells have attracted extensive attention in silicon‐based tandem solar cells. The performance of Sb2S3 devices fabricated by the vacuum method is limited by sulfur vacancies (VS) and surface oxide defects during high‐temperature processes. Herein, amorphous Sb2S3 film based on low‐temperature rapid thermal evaporation (RTE) technique is fabricated to overcome S loss. Moreover, a sulfur‐atmosphere recrystallization strategy is further developed to obtain high‐quality absorbers from the amorphous film. The element content of Sb2S3 film is completely in accord with the stoichiometric ratio (2:3), and the surface oxides are effectively suppressed, enhancing VOC and fill factor. Compared to the control directly crystallized film, the defect concentrations of the S‐recrystallized Sb2S3 film are reduced by 61%, exhibiting better uniformity and higher PN junction quality. Ultimately, the full‐inorganic Sb2S3 solar cells (FTO/TiO2/Sb2S3/Au) achieve an efficiency of 6.25%. The S‐atmosphere recrystallization process can effectively passivate bulk defects (VS and Sb2O3) and suppress recombination to improve device performance, which will provide new prospects for vacuum method‐based Sb2S3 thin film solar cells. [ABSTRACT FROM AUTHOR]

Optical properties of sol-gel deposited Barium Strontium Titanate (BaxSr1-xTiO3, BST) thin films were studied to determine their suitability as light sensors. Crystallized BST films were formed by annealing in air at 700 C for 1 h. Lattice parameters and grain sizes were determined for all the compositions. The band gap and refractive index values of the samples were determined from the optical transmission spectra for different compositions. Band gap of all the compositions were in the semiconductor range that would allow them to be used for photodiode and light sensor applications. Refractive index is reported for all the compositions. [ABSTRACT FROM AUTHOR]

Here, we propose an original method of photochemical deposition for the synthesis of metal oxides from coordination complexes sensitive to UV light. The method consists of the synthesis of zinc oxide amorphous films doped with different concentrations of copper oxide followed by annealing at 600 °C. The photo-reactivity of the samples was evaluated by the decrease of the FT-IR spectroscopy bands. The films were analyzed by scanning electron microscopy (SEM–EDX) and X-ray diffraction (XRD) to study their morphology and structures, respectively. The results show an amorphous characteristic in the photo-deposits. The optical properties show a gradual decrease of both the optical band gap and the luminescent emissions of the ZnO photo-deposits when CuO doping increases. Both properties allow a shift in absorption towards the visible and a decrease in the rate of recombination of charge carriers. The photocatalytic activity was analyzed using methyl orange and methylene blue as pollutants under a lamp that emulates solar energy. The results show that the photocatalytic activity is favored by the insertion of CuO; 46.6 and 93.0% efficiency in the photodegradation of methyl orange and methylene blue, respectively, were reached at 1.0 mol % of CuO with respect to pure ZnO. These differences in degradation efficiency respond to the chemical stability of the dyes. Finally, the use of appropriate scavengers suggests an oxidative route in the dye degradation mechanism. [ABSTRACT FROM AUTHOR]

The film–substrate architectures are a promising design for improving tensile ductility of metallic glasses. Recent experiments have shown that cracking of amorphous metallic glass films is the major fracture mode of the film–substrate systems subjected to tensile loading. In this study, calculations are carried out for multiple cracking of an amorphous metallic glass film bonded to a ductile substrate. The pressure sensitive yielding, plastic dilatancy and post-yield strain softening caused by evolution of free-volume of the amorphous film are accounted for; furthermore, the competition between brittle cleavage and shear band induced cracking in the amorphous film is considered in the numerical analyses. It is found that for thin films, the multiple cracking behavior is associated with development of shear bands, and small crack spacing involves interaction of multiple shear bands, which can further activate the mechanism of substrate confinement and leads to large critical strain for film cracking. The multiple cracking in thick amorphous films is governed by brittle cleavage mechanism, which suppresses plastic deformation in the film and gives rise to small critical strain for film cracking. For the amorphous film with intermediate thickness, the shear band induced cracking dominates in the case of small crack spacing, while brittle cleavage mechanism is responsible for the multiple cracking of amorphous films with large crack spacing. The findings of this study shed new lights on the design of reliable film–substrate systems. [ABSTRACT FROM AUTHOR]

Amorphous Cd-doped GeS2 films were prepared by thermal evaporation. In the Raman spectra of GeS2:Cd films with nominal Cd content above 8% at high laser power densities (above 200 kW/cm2), Raman peaks of the CdS LO and 2LO phonons are observed as evidence for the formation of CdS nanocrystals in the films under laser irradiation. The nanocrystals are formed due to the photoenhanced diffusion of atoms in the GeS2:Cd films, which is caused by non-thermal photofluidity (a drastic decrease of the film viscosity under illumination) that enables the aggregation of Cd and S atoms in nanocrystals. Factors responsible for the variation of the CdS LO phonon peak as a function of laser power density are discussed. [ABSTRACT FROM AUTHOR]

Dielectric film capacitors are considered as potential candidates for advanced power electronics technology due to their extremely high-power densities and outstanding mechanical and thermal stability, but the further improvement of energy storage density is still needed. Here, a strategy is proposed to enhance the energy storage properties by introducing nanoscale polarization regions into amorphous films, which can significantly improve the maximum polarization and maintain a high breakdown strength. The (1−x) BaTiO3-xBi(Ni0.5Zr0.5)O3 ((1−x)BT-xBNZ) thin films are fabricated by the sol– gel method and the amorphous films with nanoscale polarization regions are obtained by adjusting the preparation process. Consistent with the conjecture, amorphous phase and nanoscale polarization regions in the (1−x) BT-xBNZ films are clearly observed by electron diffraction. Results show that giant recoverable energy density of 103.7 J cm−3 with high energy efficiency of 88.3% are simultaneously achieved at 8.3 MV cm−1 in 0.92BT-0.08BNZ thin films. Furthermore, the 0.92BT-0.08BNZ thin film exhibits excellent thermal stability in a wide temperature range of 20–200°C, ΔWrec/Wrec20°C < 2.2%. This work provides a novel method for dielectric thin film capacitors applied in high temperature and electric field. [ABSTRACT FROM AUTHOR]

Dielectric film capacitors are considered as potential candidates for advanced power electronics technology due to their extremely high‐power densities and outstanding mechanical and thermal stability, but the further improvement of energy storage density is still needed. Here, a strategy is proposed to enhance the energy storage properties by introducing nanoscale polarization regions into amorphous films, which can significantly improve the maximum polarization and maintain a high breakdown strength. The (1−x)BaTiO3‐xBi(Ni0.5Zr0.5)O3 ((1−x)BT‐xBNZ) thin films are fabricated by the sol–gel method and the amorphous films with nanoscale polarization regions are obtained by adjusting the preparation process. Consistent with the conjecture, amorphous phase and nanoscale polarization regions in the (1−x)BT‐xBNZ films are clearly observed by electron diffraction. Results show that giant recoverable energy density of 103.7 J cm−3 with high energy efficiency of 88.3% are simultaneously achieved at 8.3 MV cm−1 in 0.92BT‐0.08BNZ thin films. Furthermore, the 0.92BT‐0.08BNZ thin film exhibits excellent thermal stability in a wide temperature range of 20–200 °C, ∆Wrec/Wrec20 °C < 2.2%. This work provides a novel method for dielectric thin film capacitors applied in high temperature and electric field. [ABSTRACT FROM AUTHOR]

Lead halide perovskites are among the most exciting classes of optoelectronic materials due to their unique ability to form high‐quality crystals with tunable bandgaps in the visible and near‐infrared using simple solution precipitation reactions. This facile crystallization is driven by their ionic nature; just as with other salts, it is challenging to form amorphous halide perovskites, particularly in thin‐film form where they can most easily be studied. Here, rapid desolvation promoted by the addition of acetate precursors is shown as a general method for making amorphous lead halide perovskite films with a wide variety of compositions, including those using common organic cations (methylammonium and formamidinium) and anions (bromide and iodide). By controlling the amount of acetate, it is possible to tune from fully crystalline to fully amorphous films, with an interesting intermediate state consisting of crystalline islands embedded in an amorphous matrix. The amorphous lead halide perovskite has a large and tunable optical bandgap. It improves the photoluminescence quantum yield and lifetime of incorporated crystalline perovskite, opening up the intriguing possibility of using amorphous perovskite as a passivating contact, as is currently done in record efficiency silicon solar cells. [ABSTRACT FROM AUTHOR]

Zn-doped As2Se3 and As2S3 films were prepared by thermal evaporation. Their amorphous structure was confirmed by Raman spectroscopy. Zinc chalcogenide nanocrystals can be formed in the films under laser irradiation due to the photoenhanced diffusion of atoms in the arsenic chalcogenide films, which enables aggregation of Zn and S(Se) atoms in nanocrystals. For As2S3:Zn films, not only ZnS, but also ZnO crystallites can be formed under irradiation with UV laser light due to oxidation of the film surface with abundant zinc atoms. [ABSTRACT FROM AUTHOR]

The article summarizes the results of electron microscopic studies of 'in situ' crystallization of thin amorphous films. Data analysis is carried out based on the classification scheme of electron-beam crystallization of films, including structural-morphological and numerical characteristics. Layer polymorphous crystallization (as the analogue of Frank-van der Merwe growth mode), island polymorphous crystallization (as an analogue of the Volmer- Weber growth mode) and dendrite polymorphous crystallization (as an analogue of the Stransky-Krastanov growth mode) are identified. For each type of crystallization a dimensionless parameter of the relative length δ0 is determined. It is equal to the ratio of the characteristic length to the value, related to the size of the unit cell of the crystal. Based on the electron microscopic video registration of the process, kinetic crystallization curves are built for each type of the transformation. [ABSTRACT FROM AUTHOR]

Sputtered Ge2Sb2Te5 (GST) films are utilized in phase‐change devices, whereas the quantitative reproducibility of fundamental properties such as refractive index and electrical conductivity remains unsatisfactory. Herein, it is exemplified that the properties are considerably affected by sputter conditions. It seems that high‐quality amorphous films are deposited with slow dc sputtering at high voltages and low Ar pressures. It is also discussed whether the cubic GST is a degenerate or a nondegenerate semiconductor. [ABSTRACT FROM AUTHOR]

The memristor, a two-terminal memory device with units of resistance, has continued to gain momentum as simpler and more versatile memristive devices are discovered. Amorphous metal-oxide devices have emerged as potential replacements for organic and silicon materials in thin-film electronics. This work presents memristive devices based on amorphous TiOx which were synthesized using a simplified sol-gel process that does not require a dry nitrogen flow step to fabricate amorphous films of titanium oxide (TiOx) for memristive devices. This simplified process significantly decreases the cost and complexity of the fabrication of memristive devices. The memristive behavior was characterized by I-V curves and read-write sequential pulses. We report on the effects of different TiOx layers on I-V curve behavior, stability, aging of the devices as well as the influence of interfaces and electrode materials in the memristive properties. Devices made as a stack of copper electrode, different TiOx layers and aluminum electrode showed best results for on/off ratio than other devices in this work, as well better stability of resistive switching properties. [ABSTRACT FROM AUTHOR]

The phenomenon of spontaneous spin reorientation in Gd–Сo amorphous films, which results from the competition between the perpendicular magnetic anisotropy and shape anisotropy, is studied. It is shown that the reorientation occurs via the formation of a fine-grained nonuniform magnetic structure called hypercritical state in a wide temperature range. Magnetic domains in the spin-reorientation region are characterized using magnetic and magneto-optical measurements. Based on the experimental magnetometric data and results of simulating the temperature dependences of spontaneous magnetization, the phase diagram of the films containing 16–26 at % Gd is constructed, which, being plotted on coordinates elemental composition—temperature, exhibits the ranges of existence of the perpendicular anisotropy, transition magnetic anisotropy (hypercritical state), and planar magnetization state. [ABSTRACT FROM AUTHOR]

Amorphous Fe−Co−P−C films supported on carbon fiber paper were prepared by using an inexpensive conventional magnetron co‐sputtering technique, and the effects of the Co content on electrocatalytic performance were assessed. These Fe80-x CoxP13C7 (x=20, 40 or 60) films performed well as electrocatalysts and exhibited good durability during the oxygen evolution reaction in 1.0 M KOH. Increases in the Co concentration improved the electrocatalytic activity, and the Fe20Co60P13C7 film produced a low overpotential of approximately 310 mV at 10 mA cm−2, with a low Tafel slope of approximately 31 mV dec−1. This material also maintained a constant overpotential for at least 20 h. Based on the results of this study, these materials represent a new approach to the development of highly efficient, inexpensive catalysts for water electrolysis. [ABSTRACT FROM AUTHOR]

The architecture consisting of films resting on a ductile substrate is ubiquitous in a wide variety of applications. A typical failure mechanism of such a structure is cracking of the films. In this study, the calculations for the notch tip fields in a metallic glass film deposited on a ductile substrate are carried out to explore the fracture mechanisms of the amorphous films. The amorphous film is characterized by an isotropic elastic-plastic model which captures the pressure sensitive yielding and post-yield strain softening behavior of metallic glasses, and the substrate is taken to be an elastic-plastic solid with the flow rule given by von-Mises flow theory. It is found that the thick amorphous films exhibit high opening stress and small plastic deformation, indicating that brittle cracking of the films tends to be the dominant fracture mode. Whereas, the low opening stress is observed and shear bands develop in the case of thin amorphous films, implying that the cracking caused by shear bands governs the fracture of films. We further revealed that the pressure sensitive yielding plays an important role in the fracture of amorphous films; large degree of pressure sensitivity enables low opening stress and enhanced plastic deformation in the films, increasing the propensity of formation of shear bands. The findings of this study provide plausible explanations for the experimentally observed fracture behavior of amorphous films on ductile substrates, and shed new light on the fracture mechanisms of such a structure. • The effect of film thickness on fracture mechanisms is revealed. • The role of pressure sensitive yielding in formation of shear bands is elucidated. • The mechanisms responsible for transition in failure modes of films are identified. [ABSTRACT FROM AUTHOR]

Abstract Structural and electrical properties of amorphous TiAl films with 50 at.% Ti and 50 at.% Al deposited with a compound target by dc magnetron sputtering were characterized by X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy, and electrical measurements. We found that as-deposited Ti 0.5 Al 0.5 films with a thickness below 1000 nm were amorphous, whereas small hexagonal crystallites could be detected in thicker films. Such layers exhibited a compressive stress which increased with decreasing the thickness of TiAl. The behaviour of stress with the temperature was qualitatively similar in films independently on their thickness. Thermal annealing at 300 °C reduced the initial compressive stress and no changes of the phase of TiAl were observed. We correlated these observations with annihilation of point-like defects created by the deposition in thin Ti 0.5 Al 0.5 films or with appearance of nanocrystallites in the amorphous matrix of TiAl. These effects were also responsible for the changes of the resistivity observed at elevated temperatures. We showed that a heat treatment induced by an electronic current with a density of about 2 MA/cm2 led to the crystallization of TiAl films independent on their thickness. A similar effect could be achieved by annealing the samples at 520–550 °C in air or N atmosphere. A significant drop of the resistivity down to 90 μΩcm was detected in the annealed films at room temperature. XRD confirmed that two different phases of TiAl (γ and α 2) with randomly oriented crystallites appeared in the annealed films. Highlights • Structural and electrical properties of amorphous TiAl films were investigated. • Crystallites of hexagonal structure were observed in films thicker than 750 nm. • Stress and resistivity of amorphous TiAl were reduced after annealing at 300 °C. • Crystallization of TiAl occurs by annealing at about 520–550 °C. • XRD confirms the existence of only γ -TiAl in the annealed samples. [ABSTRACT FROM AUTHOR]

We report the study of interlayer coupling between Co 20 Fe 60 B 20 (CoFeB262) layers and the resulting magnetic properties of trilayer [CoFeB262 ( y nm)/Cr ( x nm)/CoFeB262 (20 nm)] films with symmetric ( y  = 20) and asymmetric ( y  = 100) structures. All as-deposited CoFeB262 films exhibit amorphous structure. Surface topography studies display clear and uniform surfaces with very fine and sparsely dispersed nanosized grains. The average surface roughness of the CoFeB262 films increases marginally as y is increased from 20 to 100 nm. The shape of magnetic hysteresis ( M - H ) loop of single-layer CoFeB262 ( y nm) films transforms from rectangular shape for CoFeB262 (20 nm) film to transcritical one for CoFeB262 (100 nm) film. This is mainly due to change in magnetic domain structure from in-plane magnetization to dense stripe domain with increase in y . On the other hand, the shape of the M - H loops in trilayer films strongly depends on x , y and temperature. All symmetric trilayer films show single magnetization reversal process at room temperature with a kink in the first quadrant for films with x  < 1. Coercivity ( H C ), saturation field ( H sat ) and remanence ratio ( M R / M S ) show oscillatory behaviors as a function of x . For asymmetric films, the transcritical loop changes into rectangular one after the introduction of Cr interlayer. This also causes a large reduction in H sat and enhances M R / M S sharply. Temperature dependent M - H loops at low temperatures reveal the disappearance of the kink in symmetric trilayer films and the formation of additional steps in asymmetric trilayer films with x  > 0.5. The relative increase in H C with decreasing temperature is found to be larger for symmetric films as compared to asymmetric ones. The observed results are explained on the basis of change in the interlayer coupling between CoFeB262 layers with change in x , y and temperature dependent interfacial strain, which modifies the nature of interlayer coupling. These results also demonstrate that dense stripe domain of thicker CoFeB262 layers can be easily converted into simple in-plane magnetization using trilayer thin films. [ABSTRACT FROM AUTHOR]

The morphology and kinetics of crystals growth in amorphous films of Cr2O3, ZrO2, and HfO2 have been studied by the methods of transmission electron microscopy ("in situ") with video registration of structural changes. Based on the frame-by-frame analysis of the video the kinetic curves of the phase transformations have been constructed, which reveal typical features of the main crystallization modes: layer (Cr2O3), island (ZrO2), and dendrite (HfO2) polymorphous crystallization. For each mode the numerical values of the relative crystallization lengths (2036 for Cr2O3, 77 for ZrO2 and 4180 for HfO2) are determined. The crystal growth modes at electron-beam heating of amorphous films are compared with crystal growth modes on substrates at vapor condensation in vacuum (Frank-van der Merwe, Volmer-Weber and Stranski-Krastanov growth modes). [ABSTRACT FROM AUTHOR]

The effects of mold cavity geometry and imprinting temperature on imprinted amorphous ZrCu films are studied using molecular dynamics simulations based on the many-body embedded-atom potential. The effects are investigated in terms of shear strain, flow field, loading force, relationship between pattern filling height and mold displacement, and pattern elastic recovery. The simulation results show that imprinting should be conducted at high temperatures (slightly above the glass transition temperature), followed by unloading at 300 K. Imprinting at higher temperatures shortens the pattern filling time, decreases the required loading force, and lowers the shear strain concentration inside the films. Unloading at 300 K leads to a low pattern elastic recovery, which increases with increasing temperature. Imprinting using a groove pattern on the mold requires a larger loading force and less filling time compared to those required when using a tip-like pattern on the mold. For imprinting using a tip-like pattern on the mold at temperatures of 300–475 K, shear transformation zones form inside the films in the form of a ring surrounding the mold. [ABSTRACT FROM AUTHOR]

In-Sb-Te when is a thin film presents a huge difference in its electrical resistivity when transform from the amorphous (insulating) to the crystalline (conducting) phase. This property made this system one of the main phase-change materials used in the data storage industry. The change in the electrical conductivity is probably associated to a change in the bonding geometry of some of its constituents. To explore this point, we present in this work an study of the bonding geometry of In atoms in In-Sb-Te films by means of In K -edge X-ray absorption near edge structure (XANES) spectroscopy using synchrotron radiation in both as deposited (amorphous) and crystalline thin films obtained as a result of resistance ( R) vs temperature (T) measurements. Comparison of the XANES spectra obtained for ternary amorphous films and binary crystalline reference films suggests that in amorphous films the bonding geometry of In atoms is tetrahedral-like. After the thermal annealing has been carried out the differences in the XANES spectra of the as deposited and the annealed films indicate that the bonding geometry of In atoms changes. Based on X-ray diffraction results and ab initio calculations in the framework of the Density Functional Theory (DFT) we show that the new coordination geometry is associated with a tendency of In atoms towards octahedral-like. [ABSTRACT FROM AUTHOR]

We report the preparation of MoS x thin films with reactive pulsed laser deposition (RPLD), an original technique that allows us to investigate the correlation between key MoS x properties, such as the composition, morphology, and local structure, and the catalytic performance in the hydrogen evolution reaction (HER). The use of two geometries of normal angle (NA) and sliding angle (SA) for the deposition by laser plume from a Mo target on a glassy carbon substrate made it possible to regulate the characteristics of MoS x films (1.5 ≤ x ≤ 10) by varying the H 2 S pressure and thus to circumvent the limitations inherent in traditional pulsed laser deposition. Amorphous MoS x < 2 , quasi-crystalline layered MoS 2 , disordered as well as rather perfect Mo 3 –S clusters, and sulfur clusters were formed. The films containing locally ordered clusters with a higher content of bridging S 2 2 − and apical S 2 − ligands could be prepared by SA RPLD. This film was demonstrated to be the most efficient electrocatalyst, possessing a lower overpotential of − 130 mV at a current density of − 1 mA/cm 2 , a Tafel slope of 44 mV/dec, and a quite high exchange current density of ~ 1.2 μA/cm 2 . The preparation of a low-resistance MoS x underlayer by NA RPLD made it possible to increase the catalytic performance of a bilayer coating by 10%. [ABSTRACT FROM AUTHOR]

Initial stages of vacuum condensation of As-S amorphous films on carbon substrates at the stages of nucleation and formation of condensed phase islands are studied using the electron microscopy technique. Two stages of the processes of critical nuclei formation were found: intense primary nucleation and slow secondary nucleation that occurs in parallel with the growth of the formed nuclei. The sizes of the critical nuclei of the amorphous As-S films, the primary nuclei density, the size distribution of the condensed phase islands at the moment of the nucleation processes termination and the mean diffusion length for different atomic particles of the As-S vapor phase on the substrate surface were determined. The results obtained show that at room condensation temperatures most of various multi atomic particles of the AsnSm vapor have rather high diffusion mobility over the carbon substrate surface. Therefore, when simulating the condensation processes, the As-S materials could be considered as a non-equilibrium two-dimensional gas with an extremely complicated chemical composition. [ABSTRACT FROM AUTHOR]

Different SiC thin film structures were obtained depending on the deposition techniques. Crystalline films were grown using a Pulsed laser deposition (PLD), in contrary the sputtering DC magnetron method allow to have an amorphous films (a-SiC:H and a-Si 1−x C x :H). A comparative study of the structural and optical characteristics of the elaborated films has been performed. The energetic application possibilities such as blue or multicolor LEDs have been explored. Different techniques have been used to investigate the elaborated films such as SEM-EDS, SIMS, photoluminescence and spectral response. [ABSTRACT FROM AUTHOR]

The mechanism of charge transport in MIS structures on the basis of thin hafnium and zirconium oxide films is studied. It is shown that transport in the studied materials is limited by phonon assisted tunneling between traps. From the comparison of experimental current-voltage characteristics of MIS structures n-Si/HfO/Ni and n-Si/ZrO/Ni, the estimated, thermal, and optical energies of traps are determined. It is shown that oxygen vacancies are localization centers (traps) of charge carriers in HfO and ZrO. [ABSTRACT FROM AUTHOR]

Amorphous bismuth-doped Al 2 O 3 thin films have been fabricated by atomic layer deposition method. The dielectric constant of the samples increases with the concentration of bismuth. Detailed electric processes are discussed based on the impedance spectroscopy and equivalent circuit model. It is found that the universal dielectric response (UDR) is ubiquitous in amorphous Al 2 O 3 . The dimensionality of the conduction space associated with the UDR process is not affected by the bismuth doping, but the alternating current conductivity associated with the UDR process increases with the bismuth concentration. The enhancement of dielectric properties is attributed to the 6 s lone pair electrons of bismuth. The result of capacitance vs. voltage measurement demonstrates that the bismuth-doped Al 2 O 3 film is suitable for the insulation layer in metal-oxide-semiconductor structure. [ABSTRACT FROM AUTHOR]

We report on the spin-to-charge conversion (SCC) in Mo 0.25 W 0.75 Te 2- x (MWT)/Y 3 Fe 5 O 12 (YIG) heterostructures at room temperature. The centimeter-scale amorphous MWT films are deposited on liquid-phase-epitaxial YIG by pulsed laser deposition technique. The significant SCC voltage is measured in the MWT layer with a sizable spin Hall angle of ∼0.021 by spin pumping experiments. The control experiments by inserting MgO or Ag layer between MWT and YIG show that the SCC is mainly attributed to the inverse spin Hall effect rather than the thermal or interfacial Rashba effect. Our work provides a novel spin-source material for energy-efficient topological spintronic devices., (© 2023 IOP Publishing Ltd.)