Chemistry of CdS/CuInSe[sub 2] Structures as Controlled by the CdS Deposition Bath

Electrodeposited samples have been used as substrates for CdS growth from alkaline solutions where the ratio of thiourea, or TU, to cadmium sulfate, has been varied systematically from 10 to 100. Analysis of the surface and interface chemistry as a function of the CdS bath deposition conditions has been performed by X-ray photoelectron spectroscopy. An increase in the surface coverage, without appreciable chemical modifications, can be obtained by increasing the thiourea to cadmium sulfate proportion in the CdS growth solution. As this ratio increases, the proportion of and secondary phases detected on the samples decreases with respect to water and the main CdS compound, but carbonate and cyanamide impurities incorporation increases at the near-surface region.