The effect of the gaseous medium composition on the electrically conductive properties of In2O3-Ga2O3 films obtained by chloride vapor phase epitaxy has been studied. In the temperature range of 100-550ºC the In2O3 -Ga2O3 films exhibit high sensitivity to H2, NH3 and CO possessing high-speed performance and low-base-resistance. A qualitative mechanism for the sensitivity of In2O3-Ga2O3 films to gases is proposed.

The effect of ambient humidity on the electrical conductive properties of α-Ga2O3 and α-Ga2O3/ε-Ga2O3 structures has been studied. Polymorphic Ga2O3 epitaxial layers were deposited by chloride vapor phase epitaxy on sapphire substrates. Pt and Pt/Ti were used as contacts. It was found that the Pt/α-Ga2O3/Pt and Pt/Ti/α-Ga2O3/ε-Ga2O3/Ti/Pt structures exhibit a high sensitivity of the current – voltage characteristics (I–V characteristics) to atmospheric humidity in the temperature range 25–100 °C. It was found that the effect of water vapor on the I–V characteristics of the structures is reversible and the most significant changes in the current in the samples are observed at a relative humidity RH ≥ 60%. With increasing temperature the effect of atmospheric humidity on the I–V characteristics decreases and disappears at T > 100 °C. The experimental results obtained are explained in terms of the Grottguss mechanism.

The thin polycrystal Cr2O3 films were synthesized by RF - magnetron sputtering with followed annealing at T = 673 K in an air atmosphere. The grains diameter in the thin Cr2O3 film is 40–70 nm, Eg = 3.3±0.2 eV. In the temperature range of 303–473 K, the Cr2O3 films show high response to NO2, Н2, vapors of acetone and toluene, weakly react to CH4 and CO and have the relatively weak dependence of resistance on humidity. The qualitative model of the gases influences on the thin Cr2O3 films electrical properties was proposed.