Synthesis and Characterization of Nanocrystalline Cdi__xZn_xS Thin Films by Chemical Bath Deposition (CBD) Method

摘要

Cadmium zinc sulphide (Cd_(1-x)Zn_xS), a typical ternary II-VI semiconductor material, has considerable interest owing to their use in the fabrication of heterojunction solar cells and other optoelectronic devices. This work presents the influence of different solvent ratios of Cd and Zn on optical, structural and morphological properties of the prepared Cd_(1- x)Zn_xS thin films by a simple cost effective chemical Bath Deposition (CBD) technique on glass substrate. Nanocrystalline thin films of Cd_(1-x)Zn_xS were prepared in an alkaline medium with the molarity of 0.25M at 343K for 90 minutes with varying Cd and Zn solvent ratios. The as deposited films were characterized by UV- Visible spectra, XRD and SEM. The direct optical band gap energies of the as deposited films for different solvent ratios were found in the range of 3.2-4.1 eV. An increase in transmittance and band gap value was found with the increasing Zn concentration into CdS thin films. The XRD studies showed the both hexagonal and cubic phase structure of Cd_(1-x)Zn_xS thin films and the estimated grain size was 6.63nm. SEM micrographs reveal nearly uniform and homogeneous Cd_(1-x)Zn_xS films without any pin holes.