Record thick (up to 100 μm) epitaxial layers of a prospective semiconductor metastable Ga2O3 were grown by HVPE (Halide Vapor Phase Epitaxy) on GaN buffer layers on c-sapphire substrate. The X-ray diffraction spectra of the layers show that the structure of the layer is a pure k(ε)-Ga2O3 without any other phases. At the same time, the organization of the domain structure is noted, which manifests itself in the form of pseudohexagonal prisms with the inheritance of the orientation of the gallium nitride sublayer. Schottky diodes with a nickel contact were fabricated and the electrical and photoelectric properties of the layers were studied. Capacitance-voltage (C-V) and frequency-capacitance (C-f) dependencies have been studied, photocurrent and photocapacitance spectra have been measured.

Single-crystalline α-Cr2O3 layers were synthesized on a sapphire substrate with a basal orientation in a laboratory reactor using ultrasonic-assisted chemical vapor deposition in the temperature range of 700-850°C. The influence of the growth temperature on the structural quality of the layer was studied by X-ray diffraction. At a growth temperature of 800°C, continuous layers with a thickness of about 1 μm were obtained. The layers were transparent in the visible region with a slightly greenish tint and showed some light transmission up to wavelengths of ~350 nm. The full width at half maximum of the rocking curve for reflection 0006 was ~ 300 arcsec.