Influence of [S]/[Cd] ratio on the structural, morphological and optical properties of CdS thin films prepared by chemical bath deposition

摘要

Cadmium sulphide (CdS) thin films were deposited by chemical bath deposition method (CBD) on glass substrates at solution temperature of 75°C for 60 min. Anhydrous cadmium chloride (CdCl2) and thiourea (CS(NH2)2 wereusedas sources of cadmiumand sulphur ions respectively. The influence of [S]/[Cd] ratio in the solution on the structural, morphological, chemical composition and optical properties of these films were investigated. X-ray diffraction (XRD) studies revealed that all the deposited films were polycrystallinewith hexagonal or cubic structure and exhibited [002] or [111] preferential orientation, respectively. The filmdeposited with [S]/[Cd] ratio = 2.5 was found relatively well crystallized. It showed large final thickness and its surface morphology was composed of small grains with an approximate size of 12 to 21 nm and grains grouped together to form large clusters. Energy Dispersive X-rayAnalysis (EDAX) revealed that this film was nonstochiometric with a slight sulphur deficiency. This film exhibited also an average transmittance value of about 79%in the visible and infra red regions.