ZnO Thin Films Prepared by Thermal Oxidation Method and It's Properties Study

ZnO thin films have been fabricated by thermal oxidation of metallic Zn films at different temperatures in air. The results of X-ray diffraction (XRD) show that the film prepared at 500℃ has the best crystallinity among all the films. As oxidation temperature increases, stress along c-axis in the samples changes from the tensile to the compressive, and the conversion temperature is in the range of 450~500℃. The full width at half maximum (FWHM) of ultraviolet (UV) peak for the ZnO film prepared at 500℃ is 94.8 meV, and corresponding photoluminescence (PL) intensity ratio of UV emission to deep-level (DL) emission is as high as 162 at room temperature. The DL emission becomes dominant in the PL spectra when oxidation temperature exceeds 700℃, and the possible origin of this phenomenon is also discussed.