Structural and optical characterization of indium oxide thin films by vacuum thermal evaporation

Abstract

Indium oxide of purity 99.99% powder was used as starting material for the preparation of Indium oxide thin films using vacuum thermal evaporation technique. Ultrasonically cleaned and dried glass substrates were used for deposition of In2O3 thin films. Films were grown in vacuum of 3×10-5mbar pressure followed by annealing in air in the temperature range 573K - 873K. The crystallinity of the films were investigated using XRD. The films were found to be polycrystalline in nature and crystallizes in a cubic structure with preferred (222) orientation. The surface morphology was investigated for these films using Scanning Electron Microscope (SEM) and chemical composition of the films was estimated using EDS. The Optical transparency of these films was found to be varying with annealing temperature and at 673K the transmittance was found to be maximum. Thickness of the films was found to be 918nm. The optical band gap was also varying with annealing temperature. The PL emission spectra were taken at excitation wave length of 350nm. In2O3 thin films shown PL emission in the UV region at room temperature, which encourages development of nano scale devices in future.