Study of Some Electrical and Optical Properties For ZnO Thin Films Prepared by dc Magnetron Sputtering

Abstract

Zinc Oxide thin films have been prepared by d.c magnetron sputtering at different magnetic field. the deposition of the films prepared was carried out in dc magnetron sputtering system (Edward 306 pumping system) on heated glass substrate. The structure of the films have been studied by X-ray diffraction method. X-ray analysis has shown that the prepared films have a hexagonal structure ,and also the increasing of magnetic field leads to increase the grain size and rate of deposition ,which increase film thickness. This study included the effect of magnetic field on electrical and optical properties for the prepared films. From the study of the electrical properties ,it was shown that the resistivity decreases by increasing the value of magnetic field, and the minimum value to the electrical resistivity was 17×10-3Ω.cm at 450nm thickness and at 470Gauss magnetic field magnitude .By more increasing of magnetic field ,the resistivity increases because of the distortion in the crystalline arrangement may be happens. It was shown also increasing in values of carrier concentration (n) and mobility(µ) with increasing the magnetic field ,also we show improvement in crystalline structure and homogenous distribution of grains. The optical absorption coefficient decreased with increased magnetic field but their is a sharp increase in (α) at film thickness 450nm, this may be due to the oriented sample growth. The dependence of the transmittance on the magnetic field attributed to the change in thickness and morphology of the films. The most suitable magnetic field needs for the films to be used as transport electrodes in the solar cells is 370Gauss,which have low resistivity and high transparency.