New technique of compound semiconductor deposition from an aqueous solution by photochemical reactions

CdS films were successfully formed on a glass substrate in an aqueous solution containing S2O32- and Cd2+ ions by photochemical reaction. S2O32- ions in the growth solution absorb ultra-violet light of wavelengths shorter than about 300 nm, and the excited S2O32- ions supply sulfur atoms and electrons to the metal ions such as Cd2+. Thus, the formation reaction of the sulfide semiconductor occurs in the only illuminated region. Photochemically deposited CdS thin films were polycrystalline of hexagonal structure. The composition of the films became stoichiometric by the annealing at temperatures higher than 300 °C.