Influence of the Bath Temperature Complexing Agent Concentration on theOptical Properties of CdS Thin Films Deposited by Chemical Bath Deposition

CdS thin films were deposited onto glass substrate by the chemical bath deposition (CBD) method,using cadmium chloride (CdCl۲) as a source of cadmium, thiourea (CS(NH۲)۲) as a source ofsulfur, ammonium nitrate (NH۴NO۳) as complexing agent and ammonia as pH controller. Theinfluence of the deposition temperature (room temperature-۸۰۰C) and NH۴NO۳ concentration (۰.۵-۲.۵M) on the structural, morphological, and optical properties was investigated. The CdS thin filmsdeposited at room temperature and ۵۰۰C showed amorphous structure. Crystallite sizes wereincreased from ۴۰ to ۵۰ nm as the bath temperature increased from ۶۵۰C to ۸۰۰C. The crystallitesizes were decreased from ۳۲ to ۲۳nm by the increase of ammonium nitrate concentration from۰.۵ to ۱.۵M, and increased from ۲۳ to ۴۲nm by the increase of ammonium nitrate concentrationfrom ۱.۵ to ۲.۵M. The optical band gap was decreased from ۳.۳ eV to ۲.۴۵eV as the bathtemperature increased from room temperature to ۸۰۰C. The optical band gap was in the range of۲.۷۵-۲.۴۵, which was decreased by the increase of the ammonium nitrate concentration. Theincrease of ammonium nitrate concentration decreased the packing density of the films

Keywords:

Cadmium sulfide , chemical bath deposition , bath temperature , complexing agentconcentration , optical properties