Photochemical deposition of CdS from aqueous solutions

CdS was deposited on a glass substrate by photochemical deposition (PCD). T he substrate was held in an aqueous solution containing S2O32- and Cd2+ and was irradiated with a mercury lamp. Then a CdS film was deposited in the i rradiated region of the substrate. The deposition rate depended on various experimental parameters, such as pH of the solution, light intensity, and s tirring speed, which were investigated. Here we discuss the deposition mech anism. It was shown that the deposition rate is determined by (i) density o f nucleation sites on the substrate, (ii) light intensity, and (iii) transp ort of the ions in the solution. In the stirred solution, the former two fa ctors are dominant. It was also demonstrated that a pattern can be made on the film using a mask. This proves that PCD has good controllability and th us is well suited for fabrication of devices such as solar cells. (C) 1999 The Electrochemical Society. S0013-4651(98)06-025-X. All rights reserved.