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

Highly conductive indium oxide thin films (rho = 5 x 10(-3) Omega 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 Angstrom, s(-1)), and the oxidation has been carried out by exposing the samples to the atmosphere directly at high temperature (500 degrees 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. (C) 2000 Elsevier Science S.A. All rights reserved.