Search

The growth mechanism, microstructure, and crystal structure of the polycrystalline n -Bi 2 Te 3 thin films with thicknesses d = 15–350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi 2 Te 3 . It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d . The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5–2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n -Bi 2 Te 3 thin films of a sufficiently high quality. [ABSTRACT FROM AUTHOR]

Abstract: Poly- and single-crystal thin films of U–Mo alloys have been grown both on glass and sapphire substrates by ultra-high vacuum magnetron sputtering. X-ray and Electron Backscatter Diffraction data indicate that for single-crystal U1− x Mo x alloys, the pure cubic uranium γ-phase exists for x ≥0.22 (10wt.% Mo). Below 10wt.% Mo concentration, the resulting thin film alloys exhibited a mixed α–γ uranium phase composition. [Copyright &y& Elsevier]

Abstract: The effect of grazing incidence 4keV Ar+ ion irradiation on the early stage of Ag thin film growth on amorphous Si was investigated. The double effect of axial and surface channeling resulted in grains oriented along the 〈110〉 axis in-plane, while the (111) out-of-plane texture was maintained. A slight average tilt of the (111) out-of-plane texture axis towards the ion beam direction is proposed to result from the difference between terrace and step edge sputtering yield. The observed tilt is consistent with a minimum erosion orientation of the surface profile. [Copyright &y& Elsevier]

Abstract: Thin films of Au–Pd of varying composition were formed by electron beam physical vapor deposition. They were characterized and their application as optical hydrogen sensors was studied. In addition, parameters of sensing performance such as Pd deficiency during deposition, grain size, compositional homogeneity, and the appearance of a natural buffer layer, were examined. Following deposition, Au–Pd films exhibited high atomic intermixing, and a PdO x buffer layer formed spontaneously. This layer makes it possible to increase film thickness, which improves the intensity of the detecting signal. Accordingly, the suggested deposition method may optimize recent efforts to use Au20wt.%–Pd thin alloy film in optical hydrogen sensors. [Copyright &y& Elsevier]

Abstract: In this study, polycrystalline Cu-foil substrates are exposed to elemental Te vapor at substrate temperatures below 373 K. Auger electron spectroscopy measurements indicate that copper-telluride films are formed at the substrate surface that have a 2:1 Cu-to-Te ratio, as predicted by the Cu–Te phase diagram. When these films are annealed above about 700 K in vacuum, Te desorbs from the substrate with zero-order kinetics. An analysis of Te-desorption traces that assumes the reaction Cu2Te(s)→2Cu(s)+ αTe(ν)+1/2(1− α)Te2(ν) finds a thermal-decomposition activation energy of 217±3 kJ mol−1. These Te-desorption data are compared to the Te impingement rate calculated from Cu2Te equilibrium vapor-pressure data from the literature and found to be in excellent agreement. [Copyright &y& Elsevier]

• Polycrystalline Bi 2 MnFeO 6 thin films doped with Fe on BiMnO 3. • Leakage current characteristics and multiferroic properties. • High domain wall energies of Bi 2 MnFeO 6 thin films. Although BiMnO 3 (BMO) thin films have multiferroic properties, they also have drawbacks such as poor leakage current and ferroelectric properties. In this study, we fabricated polycrystalline Bi 2 MnFeO 6 (BMFO) thin films and investigated their leakage current characteristics and multiferroic properties. On Pt/Ta/glass substrates, BMFO thin films were preferentially (111)-oriented as a polycrystalline thin film. The BMFO thin film showed good multiferroic properties: excellent ferroelectric properties with high remanent polarization of about 19.2 μC/cm2 and typical ferromagnetic properties with remanent magnetization of about 7 × 10−3 A/m. The BMFO thin film had better leakage current characteristics than the BMO thin film. The bandgap measurements confirmed that the BMFO thin film has a band gap of 2.46 eV, which is larger than that of the BMO thin film. This is considered to be a cause of the improved leakage current characteristics of the BMFO thin film compared to the BMO thin film. [ABSTRACT FROM AUTHOR]