Temperature-dependent photoconductance and optical properties of In$_2$O$_3$ thin films prepared by autowave oxidation

The influences of ultraviolet (UV) irradiation and temperature on the electrical and optical properties in In$_2$O$_3$ films obtained by autowave oxidation were measured experimentally. The film resistance changed slightly for temperatures from 300 to 95 K, and more noticeably when the temperature was further decreased, measured in the dark. Under UV irradiation, the resistivity of the films at room temperature decreased sharply by $\sim$25 % and from 300 to 95 K, and continued to decrease by $\sim$38 % with a further decreasing temperature. When the UV source was turned off, the resistivity relaxed at a rate of 15 $\Omega$/s for the first 30 seconds and 7 $\Omega$/s for the remaining time. The transmittance decreased by 3.1 % at a wavelength of 6.3 $\mu$m after the irradiation ceased. The velocity of the relaxation transmittance was 0.006 %/s. The relaxation of the electrical resistance and transmittance after UV irradiation termination were similar. It was assumed that the dominant mechanism responsible for the change in the conductivity in the indium oxide films during UV irradiation was photoreduction.