Ellipsometric Investigation of Room Temperature Grown Highly-Oriented Anatase TiO2 Thin Films

Abstract

In this article, we have reported the structural optimization and optical properties of anatase titanium dioxide (TiO2) thin films grown by direct current magnetron sputtering on a glass substrate at room temperature (RT). The x-ray diffraction measurement revealed anatase phase of TiO2 with preferred orientation (101). The morphological, compositional and topographical properties of the samples are explored by scanning electron microscopy, x-ray photoelectron spectroscopy and atomic force microscopy, respectively. The optical properties such as refractive index n, extinction coefficient k and optical bandgap Eg are determined in the broad wavelength range of 246–1688 nm using variable angle spectroscopic ellipsometry accounting for the surface properties in the optical stack model. Moreover, the nonlinear refractive index n2 and the third-order nonlinear optical susceptibility χ(3) are determined using the Tichy–Ticha relation and Wemple–Didomenico (WDD) parameters. The ratio of the carrier concentration to the effective mass N/m* has also been determined. The current research on the optical and dispersion energy parameters of RT grown anatase TiO2 thin films is expected to have a significant impact on advanced flexible optical, optoelectronic, and photonic applications.