Deposition and characterization of cadmium sulfide thin films by chemical bath deposition

Thin films of crystalline cadmium sulfide have been deposited onto glass substrates from alkaline solutions containing cadmium acetate, ethylenediamine and thiourea under a range of conditions at temperatures from 35 to 50 degrees C. The morphology of the deposited films depends on the conditions used for growth. Calculations on the speciation of cadmium in the solutions indicate that supersaturation of hydroxy species of cadmium is an important factor determining the quality of the CdS films deposited; solutions which are supersaturated with respect to the formation of ''cadmium hydroxide'' deposit films of the best morphology. In our studies, we see little or no evidence for the growth of the particules which form the films of good morphology.