The influence of preparation conditions on the electrical and optical properties of oxidized indium thin films

Highly conductive indium oxide thin films (ρ=5×10−3 Ω cm) have been prepared by thermal oxidation in an open atmosphere of indium films deposited in vacuum by evaporation. The rate of indium film deposition was high (5 Å s−1), and the oxidation has been carried out by exposing the samples to the atmosphere directly at high temperature (500°C) for different times. Structural, optical and electrical properties of these samples were investigated. Films exhibit a (111) preferred orientation, The value of the transmittance coefficient in the visible region of the spectrum was low (50%) but, concerning the electrical properties, an interesting behaviour was observed: at temperatures above room temperature the electrical resistance depends on the sense of the electrical current flow.