Optical properties of CdIn2O4 thin films prepared by DC reactive magnetron sputtering

Transparent conducting oxides CdIn2O4 thin films were prepared by direct-current (DC) reactive magnetron sputtering from a Cd-In alloy target in Ar + O-2 atmosphere. The thickness of the films prepared in different oxygen concentration, substrate temperature and annealing treatment was calculated by an envelope method from transmission spectra. Meanwhile, the optical constants and the optical band gap of these films have been determined. It is found that the thickness of the films increases with the decrease of oxygen concentration or substrate temperature, and the optical band gap increases with the decrease of oxygen concentration or the increase of substrate temperature. After annealing treatment, the thickness decreases sharply and the band gap widens. The optical properties are sensitive to the preparing conditions and annealing treatment, which is due to the Burstein-Moss shift and many-body effect. The width of localized states E-0 is determined and the effect of band tailing is substantial. (c) 2006 Elsevier B.V. All rights reserved.