Michael D. Sharkov

Homoepitaxial β‐Ga₂O₃ films grown by mist‐chemical vapor deposition technique utilizing Ni mask as a buffer interlayer are studied. The films are successfully grown on (100) and (01) oriented gallium oxide substrates upon Ni deposition with subsequent formation of Ni sub‐micron‐island mask. The thicknesses of the (100) and (01) Ni/β‐Ga₂O₃ films are estimated as 4 and 1.5 μm, respectively. The films grown on Ni/(01) β‐Ga₂O₃ wafers have relatively high crystal perfection, while films grown on Ni/() β‐Ga₂O₃ wafers are characterized by high growth rate. Although the proposed approach deteriorates the surface morphology and crystallinity of homoepitaxial films compared to the initial substrates, it can be applied to implement some exfoliation techniques, since the epitaxial layer has a large thickness and acceptable crystal perfection.

Pt/(100) β-Ga2O3 Schottky barrier diodes were fabricated using a plate cleaved from the crystal grown by Czochralski method. Their electroconductive and photoelectric characteristics were studied. The following values were obtained: the Schottky barrier height (1.69/1.62/1.74 eV), ideality coefficient (1.09/1.14), saturation current density (9.91 × 10–15 A/cm2), diode series resistance (7.98 kΩ), and net donor concentration [(1.8–2.4) × 1018 cm–3]. The diodes demonstrate a high rectification ratio of 1010 at an applied voltage of ± 1 V and a relatively low experimental value of the leakage current density ∼10–11 A/cm2. These structures are solar-blind and also capable of operating in self-powered mode. The diodes are highly sensitive to short-wave ultraviolet radiation with a wavelength λ ≤ 265 nm. The maximum values of responsivity (20.4 A/W), external quantum efficiency (1.2 × 104%), and detectivity (9.6 × 1015 Hz0.5 × cm × W–1) of diodes were registered under exposure to irradiation at λ = 210 nm and at applied voltage of −1 V. The responsivity and external quantum efficiency values in the self-powered operation mode were 12.3 A/W and 7.2 × 103%, respectively. The diodes showed low rise and decay times in self-powered operation mode for photodiode based on Ga2O3: 14 and 30 ms, respectively.

By means of the small-angle X-ray-scattering technique, a set of two types of microcrystalline silicon samples produced for use in solar-cell panels is investigated. It is shown that, in the two...

Two samples of detonation-synthesized ultradispersed diamond have been studied using X-ray diffractometry and small-angle X-ray scattering. It has been shown based on the X-ray diffractometry data that two samples contain regions with both the diamond and graphite-like lattices. Grain radii inside both samples are evaluated from the small-angle scattering data as 30–50 nm. The samples also contain low-dimensional components. A broad Bragg peak corresponding to a set of interplanar distances from 5 to 15 nm is revealed in the small-angle scattering curve of sample no. 1. A structural model of ultradispersed diamond particles, which represents the diamond core surrounded by concentric graphite shells similar to the onionskin, is confirmed.

The possibility of a simultaneous use of X-ray diffraction and X-ray absorption techniques in order to characterize the sizes, shapes, and chemical composition of grains in a sample (the solution of...

Lithium iron phosphate LiFePO4 (triphylite) and lithium titanate Li4Ti5O12are used as components of a number of active materials in modern rechargeable batteries. Samples of these materials are...

X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different...

The domain structure of GaN/SiC hexagonal semiconductor films has been studied using small-angle X-ray scattering in order to determine possible domain configurations in a GaN/SiC film that can...