Simulation of the Optical Properties of Zn1-xCoxO Thin Films Grown Onto Glass Substrate by Ultrasonic Spray Pyrolysis

Sabrina Roguai, Abdelkader Djelloul

Abstract: Zn1-xCoxO thin films (x=0-22 at.%) were prepared using the ultrasonic pyrolysis sputtering technique. The films have a hexagonal wurtzite structure, confirmed by X-ray difraction, with an estimated average crystallite size in the range of 18-30 nm. Concerning the optical properties, by applying the Levenberg-Marquardt least squares method, the experimental transmittance data were perfectly fitted with the transmittance data calculated via a combination of the Wemple-DiDomenico model, the absorption coefficient of an electronic transition and the Tauc-Urbach model. Decreases in bandgap energy due to the presence of high concentrations of localized states in thin films were calculated from the Smakula formula

Keywords: Thin films, X-ray diffraction, Optical properties