Resistive-type structures based on gallium-oxide films are studied. The Ga₂O₃ films are produced by radio-frequency magnetron-assisted sputtering of a β-Ga₂O₃ (99.9999%) target onto unheated sapphire substrates with preliminarily deposited platinum electrodes. The data on the structure and phase composition of the films are obtained immediately after sputtering and after annealing in argon at 900°C for 30 min. The current–voltage characteristics are recorded in the dark and upon exposure to radiation at the wavelength λ = 254 nm. It is shown that, after annealing, the photocurrent increases by an order of magnitude. The lack of sensitivity of the structures to radiation in the visible wavelength region (λ = 400 nm) is verified experimentally.

The effect of oxygen plasma on gallium oxide films formed by electrochemical oxidation of n-GaAs wafers with a donor concentration N _d = (1–2) × 10¹⁶ cm⁻³ has been investigated. It is shown that the treatment in an oxygen plasma at a temperature of 50–90°C increases the concentration of β-phase crystallites, which causes an increase in the permittivity, a decrease in the dielectric dissipation factor, and a change in the conductivity of GaAs-〈gallium oxide〉-metal structures.

The effect of annealing and oxygen plasma on the electrical characteristics of gallium oxide films has been investigated. Ga₂O₃ films with thicknesses of 200–300 nm were formed by the anodic oxidation of n-GaAs wafers with the donor concentration N _d = (1–2) × 10¹⁶ cm⁻³. It is shown that, after annealing at 900°C for 30 min, the gallium arsenide films contain only the β Ga₂O₃ phase. The effect of the duration of oxygen plasma treatment prior to annealing on the nucleation of β-phase crystallites with different orientations has been studied. It has been established that the electrical conductivity of the Ga₂O₃ films can be managed by annealing and variation in the duration of oxygen plasma treatment. It is shown that the response of the V/Ni-GaAs-Ga₂O₃-V/Ni structure to a mixture exhaled by a person depends on the value and sign of the potential on the control electrode.

The effect of doping Mg, Se, and Ca by diffusion into ZnGeP₂ on the optical damage threshold at a wavelength of 2.1 μm has been studied. It has been shown that diffusion-doping with Mg and Se leads to an increase in the laser-induced damage threshold (LIDT) of a single crystal (monocrystal), ZnGeP₂; upon annealing at a temperature of 750 °C, the damage threshold of samples doped with Mg and Se increases by 31% and 21% from 2.2 ± 0.1 J/cm² to 2.9 ± 0.1 and 2.7 ± 0.1 J/cm², respectively. When ZnGeP₂ is doped with Ca, the opposite trend is observed. It has been suggested that the changes in the LIDT depending on the introduced impurity by diffusion can be explained by the creation of additional energy dissipation channels due to the processes of radiative and fast non-radiative relaxation through impurity energy levels, which further requires experimental confirmation.

The current-voltage (I–V), capacitance-voltage (C–V), and conductance-voltage (G–V) characteristics of metal/Ga _x O _y /GaAs/metal structures are investigated. Gallium-oxide films with a thickness of 150–170 nm are deposited by the thermal evaporation of Ga₂O₃ powder onto n-type GaAs substrates with the donor concentration N _d = 2 × 10¹⁶ cm⁻³. Treatment of the Ga _x O _y films in oxygen plasma causes a decrease in both the forward and reverse currents and a shift of the C–V and G–V curves to higher positive voltages. The Fermi level at the insulator/semiconductor interface in the structures under study is unpinned. The density of states at the Ga _x O _y /GaAs interface is N _t = (2–6) × 10¹² eV⁻¹ cm⁻².