X-ray photoelectron spectroscopic studies of sprayed CdS films

The chemical composition of sprayed CdS films has been evaluated using X-ray photoelectron spectroscopy. The general impurity content in the film is discussed, throwing light on the pyrolysis reaction involved in CdS deposition. Further, the stoichiometry of these films is studied as a function of process parameters such as pyrolysis temperature, Cd/S ratio in the solution, deposition rate and film thickness. A definite correlation is observed between composition and process parameters. The compositional variation appears to be related to the structure of CdS films as well as the growth mechanism. The effects induced by annealing in nitrogen, hydrogen and ambient air are also discussed. Hydrogen and nitrogen annealing is responsible for oxygen desorption from CdS. On the other hand air annealing induces stoichiometric variations along with oxygen intake in the films.