Optical properties of CdS thin films deposited by chemical bath deposition

In this work, the structural and optical properties of CdS thin films deposited on the glass substrate bychemical bath deposition method were investigated. Precursors were Cadmium Chloride (CdCl2) as cadmium source,Thiourea (CS(NH2)2) as sulphur source, ammonia nitrate (NH4NO3) as buffer salt and ammonia as pH controller. Theinfluence of NH4NO3 concentration on the structure, morphology and optical properties were investigated by x-raydiffraction (XRD), field emission scanning electron microscopy (FE-SEM) and uv-visible (uv-vis) respectively. XRDstudies revealed that all the deposited films exhibited (002) preferred orientation. Crystallite sizes were decreased from48 t0 31nm by the increasing the ammonia salt concentration, because of the slow deposition rate. Uniformity of CdSthin films was decreased by increasing ammonia salt cincentration. Morphology of CdS thin films was spherical.Optical band gap were in the range of 2.75-2.45, which were decreased by increasing the ammonia salt concentration.

Keywords:

cadmium sulphide , chemical bath deposition , buffer salt , optical band gap