Abstract

Abstract The objective of this research is studying the effects of film thickness on the structural and optical properties for nano ZnO films prepared by d.c magnetron sputtering technique on glass substrates. Thicknesses (t) of ZnO thin films were altered by varying the deposition time from 45 min to 90 min (t=75,150,200 and 250) nm and are determined using optical method. The X-ray diffraction spectra show that ZnO thin films are polycrystalline with the hexagonal structure and show a good c-axis orientation perpendicular to the substrate. The most preferential orientation is along the (002) direction for all sputtered deposited ZnO films, in addition another peaks appear at thickness 200 and 250 nm with orientations in (102) and (110) planes. General observations indicate that microstructure parameters, such as grain size, depend sensitively on the thickness of the film. The optical properties of nano ZnO thin films have been investigated by UV/VIS spectrometer and the band gap values are found to be with the range of 3.27 eV to 3.44eV.The ZnO film of all thickness has transmittance over 85% in the visible region, and the refractive index is about 2.1.