Structure of ZnO films prepared by oxidation of metallic Zinc

ZnO is an n-type, wide band gap semiconductor that exhibits electrooptic and piezoelectric properties and it has a gamut of applications. In this paper, ZnO films were prepared by oxidizing the Zn film deposited by thermal evaporation on glass substrates. The oxidation of Zri films was carried out at different temperatures in two different atmospheres namely oxygen and ozone. The oxidized samples were characterized with regard to their microstructure, phase(s) present, and transmittance in the wavelength range of 200-1000 nm. Zn films have hexagonal phase and flake like structure. After oxidation, wurtzite phase of ZnO is formed. Texture and structure of ZnO films are shown to be dependent on the temperature, time for oxidation and type of the oxidant. The XRD pattern of these films shows the peaks corresponding to both Zn and ZnO phases that indicate incomplete oxidation of the Zn films. Transmittance of these films is low due to incomplete oxidation and impurities present in the starting material. (C) 2002 Elsevier Science Ltd. All rights reserved.