A systematic study on chemically deposited cadmium sulfide (CdS) thin film

In this work, the conventional chemical bath deposition (CBD) technique and its growth parameters were systematically studied to deposit CdS thin films on the glass substrate. The samples were prepared using a simple aqueous solution containing cadmium sulfate (CdSO 4 ·8H 2 O), thiourea [SC(NH 2 ) 2 ], ammonium sulfate [(NH 4 ) 2 SO 4 ] as a source of cadmium, sulfur, and a complexing agent, respectively. The deposited films were characterized to study the surface morphology, crystallographic structure, chemical composition, optical and electrical properties. Through this study, the structure was determined to cubic with (111) preferential orientation and the crystallinity of the films was improved with the increase of film thickness. The transmission spectra were recorded in the range of wavelength 300–600 nm. The optical bandgap of the optimized CdS films was varied from 2.43 to 2.74 eV. All the films exhibit n-type of conductivity which was found in the order of 10 –4 to 10 –5 (1/Ω-cm), suggesting that it would be suitable for the buffer layer in thin-film solar cells.