Investigation of zinc oxide thin film by spectroscopic ellipsometry

Abstract

ZnO films were deposited on glass substrates by magnetron RF-sputtering. An accurate determination of the optical constants of these films is extremely important prior to its application in optical devices and spectroscopic ellipsometry provides a reasonably accurate method for the determination of optical constants of thin films. In this study, we present the results gained by analyzing spectroscopic ellipsometry of ZnO thin film combined with comparison of transmission spectroscopy measured on a UV-VIS-NIR spectrophotometer. Ellipsometry data have been fitted with a model including a glass substrate and a ZnO film plus a surface void layer on top. From this fitting the refraction index (n), extinction coefficient (k) and thickniess (d) of the sputtered ZnO films were determined. By using the gained n, k and d values the transmission spectrum was theoretically calculated and compared with the experimentally obtained transmission one. As a result of the combined spectroscopic ellipsometry and transmission analysis, there was the good correlation in comparison.