Physical properties of spray pyrolysed ZnO thin films obtained from nitrate, acetate and chloride precursors: Comparative study for Solar Cell Applications

Abstract

ZnO thin films prepared using zinc chloride, zinc acetate and zinc nitrate precursors have been successfully synthesized by Spray Pyrolysis method. Films depositions were carried out on glass substrates at 350◦C. Structural properties of ZnO films were investigated by X-ray diffraction (XRD), confirming that all precursors have an Hexagonal Wurtzite structure. The obtained films were oriented along the preferential (002) crystallographic plane. The phase purity was also confirmed by X-ray photoelectron spectroscopy (XPS), Ultra Violet-Visible, and Energy Dispersive X-ray spectroscopy measurements (EDX). The optical measurement revealed that films have average transmittance of 58%, 78% and 65% for zinc chloride, zinc acetate and zinc nitrate, respectively. The band gap values obtained are 3.19, 3.17 and 3.23 eV for ZnO films using zinc acetate, zinc chloride and zinc nitrate precursors, respectively. Additionally, the refractive index and extinction coefficient of the ZnO films for all precursors have been explored.