EFFECT OF CADMIUM ION CONCENTRATION ON THESTRUCTURALAND OPTICAL PROPRTIES OF CdS THIN FILMS BYCHEMICALBATHDEPOSITION METHOD

Abstract

Cadmium Sulfide (CdS) thin films were successfully deposited on glass substrates at four different concentration of cadmium ion (Cd 2+ ) by chemical bath deposition technique at a bath temperatureof80 0c for 50 minutes. The reagents used for the deposition were cadmium sulphate (CdSO4) for Cd2+source, thiourea (CS(NH2)2) for S 2- source and ammonia (NH3) as complexing agent. Thesynthesized thin films were characterized by XRD and UV-Vis Spectrophotometer. TheXRDanalysis of CdS thin films revealed that cubic crystal structure with preferred orientationalongthe(111) plane and the crystalline size increases in the range of 8.78nm to 18.98nmwith increasingcadmium ion (Cd 2+ ) concentration in the solution. Moreover, after the increase of Cd2+ionconcentration one peak of CdO with cubic structure appeared. Also the dislocation density(δ) andstrain (ε) were calculated. From VU-Vis Spectrophotometer study, the optical band gap valuesofCdS thin films decreased in the range of 2.0eV to 1.85eV with increasing the cadmiumion(Cd2+)concentration.