Effects of Molarity Variation on the Optical Property and Topography of ZnO Thin Films Deposited Via Spray Pyrolysis

Abstract

Thin film deposition is very crucial in fabricating ZnO-based electronic devices such as sensors, piezoelectric generators and photovoltaic solar cells. In this study, ZnO thin films were deposited in glass substrates via spray pyrolysis with varying zinc acetate dihydrate concentration. The films exhibited high absorption in the near-UV region (292-400 nm), yet maintaining high transmission over the visible spectra with maximum attenuation of only 33%. The optical bandgap energy of the deposited ZnO films was almost constant at around 3.25 - 3.27 eV. At higher molarity, the optical adsorption is greater especially at near-UV region while the optical transmission is lower at the visible light region. SEM images reveal that the ZnO film is composed of tiny particles. Generally, the film becomes rougher at higher zinc acetate concentration due to the formation of larger ZnO particles.