CHARACTERIZATION OF ZNO FILMS PREPARED BY DE REACTIVE MAGNETRON SPUTTERING AT DIFFERENT OXYGEN PARTIAL PRESSURES

ZnO films have been deposited on the glass substrates by de reactive magnetron sputtering method at different oxygen partial pressures (5 x 10(-4) to 3 x 10(-3) mbar). The deposited films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance and reflectance, respectively. XRD results show that all the films are oriented with the c-axis perpendicular to the substrate. As oxygen partial pressure is increased, the grain size and diffraction peak intensify decrease. SEM results show that the films have columnar structure and the average crystallite dimension in the direction perpendicular to the c-axis decreases as oxygen partial pressure is increased. The film transmittance increases as oxygen partial pressure is increased. By comparing the diffuse transmittance and reflectance spectra of the films it has been found that the light loss in the film is mainly due to Rayleigh type scattering and the scattering decrease as the oxygen partial pressure is increased.