THE EFFECT OF DEPOSITION TEMPERATURE ON STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILM BY USING CHEMICALBATH DEPOSITION METHOD

Abstract

Cadmium sulphide is an intrinsic n-type semiconductor material with the chemical formula CdS. CdS thin films where deposited on glass substrates using cadmium sulphate as the cadmium ion source, thiourea as the sulphur source, and ammonia as the complexing agent through the chemical bath deposition method . The effect of deposition temperature ranging from 400C to 800C in 100C intervals on the structural and optical properties of thin films was investigated. The films were annealed at 3000C for 1:30 hours. The CdS thin films were characterized using XRD for structure and UV-VIS spectrophotometer for optical property determination. Optical investigations revealed that CdS exhibited high absorption in the visible region, with the optical band gap from 1.80 eV to 1.37 eV as the temperature increased. This indicates an inverse relationship between deposition temperature and band gap energy, making these thin films suitable as absorber materials for solar cell fabrication. XRD analysis showed that the deposited CdS thin films had a simple hexagonal crystal structure with preferred orientation along the (002) plane. The intensity of the sharp peak indicates that the sample is highly crystalline. Additionally, the crystalline size of the CdS thin films increased with the higher bath temperatures. Generally, varying the deposition temperature had effect on the structural and optical properties of cadmium sulphide thin films.