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

Abstract

Electrodeposited CuInSe2CuInSe2 samples have been used as substrates for CdS growth from alkaline solutions where the ratio of thiourea, SC(NH2)2SC(NH2)2 or TU, to cadmium sulfate, CdSO4,CdSO4, has been varied systematically from 10 to 100. Analysis of the CdS/CuInSe2CdS/CuInSe2 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 CuInSe2CuInSe2 surface coverage, without appreciable CuInSe2CuInSe2 chemical modifications, can be obtained by increasing the thiourea to cadmium sulfate proportion in the CdS growth solution. As this [TU]/[CdSO4][TU]/[CdSO4] ratio increases, the proportion of Cd(OH)2Cd(OH)2 and CdSO4CdSO4 secondary phases detected on the CdS/CuInSe2CdS/CuInSe2 samples decreases with respect to water and the main CdS compound, but carbonate and cyanamide impurities incorporation increases at the near-surface region. © 2001 The Electrochemical Society. All rights reserved.