Optical and structural properties of ZnO thin films grown by magnetron sputtering: Effect of the radio frequency power

Abstract

In this work we studied the effect of the magnetron sputtering radio frequency (RF) power on the optical and structural properties of ZnO thin films. The films were characterized by X-ray diffraction (XRD), X-ray reflectometry (XRR) and UV–vis spectroscopy. The XRD results indicate that the films have grown in a wurtzite hexagonal phase with high c-axis (002) preferential orientation. The thickness, roughness and density of the films were measured by XRR. The roughness and density of the films have a strong dependence on the RF-power. According to the UV–vis analysis, in the visible region the absorbance is not noticeably affected by the RF-power whereas in the ultraviolet region the absorbance is strongly diminished with the increase of the RF-power. The bandgap values for the films are close to 3,3eV with no significant variation with applied RF-power.