Deposition of some transparent conducting oxide thin films by a simple spray pyrolysis technique and their characterizations for optoelectronic applications

Abstract

In this study, spray pyrolysis method has been employed for the deposition of some transparent oxide thin films like ZnO, CdO and SnO2 onto glass substrate under atmospheric pressure using zinc acetate, cadmium acetate and tin chloride precursors at relatively low temperature around 200~350°C. Films of various thicknesses have been obtained by varying the deposition time and concentrations, while all other deposition parameters such as spray rate, carrier gas pressure and distance between spray nozzle to substrate were kept constant. Surface morphology, structural and optical properties of the as-deposited thin films has been studied by Scanning Electron Microscopy (SEM) attached with an EDX, XRD and UV visible spectroscopy. The elemental composition of the samples studied by EDX reveals that the as-deposited films are good homogeneous and stoichiometric. The SEM micrograph shows uniform deposition and scattered nano fiber around the nucleation centers of the ZnO film and small crystallites and agglomeration of the grain particles for pure cadmium oxide and tin oxide samples. The optical band gaps of the ZnO, CdO and SnO2 thin films were found to be around 3.4 eV, 2.53 eV and 3.75 eV respectively. The obtained experimental results also discuss the suitability of these films as transparent and conducting window materials in optoelectronics applications.