Influence of oxidation conditions on the properties of indium oxide thin films

Indium oxide (In2O3) thin films have been prepared by thermal evaporation of indium in vacuum on a glass substrate at room temperature, followed by thermal oxidation in air. It was experimentally established that the heating velocity during the oxidation process has a strong influence on the electrical and optical properties of films as prepared. The temperature was increased from room temperature to 450 degrees C, with velocities ranging between 0.1 degrees C/s and 0.5 degrees C/s. In2O3 thin films as obtained have been examined for optical transparency function on wavelength. The calculated values of optical band gap range between 2.99 and 3.31 eV. Electrical conductivity measurements have also been carried out on the above oxide thin films as a function of temperature. Both the electrical and optical studies showed that In2O3 thin films with higher transparency and electrical conductivity are obtained at higher oxidation velocities. Also, the experimental results show linear dependences of transmission coefficient on the oxidation velocity. (C) 2000 Elsevier Science B.V. All rights reserved.