Electrodeposition of ZnS-ZnO2 film mixtures onto monocrystalline n-InP substrates through the simultaneous electroreduction of dioxygen and sulfur in the presence of zinc ions in dimethyl sulfoxide solution is reported. The films were thick, compact, transparent, and with a flat morphology. The mixture of phases was confirmed by the analysis of the reflection high-energy electron diffraction patterns. The optical absorption gave an E-g value of 3.47 eV, which agrees with the presence of ZnO in the mixture. The properties of the films suggest it might be a good alternative to replace the CdS window layer in Cu (In, Ga) Se-2-based photovoltaic devices. (c) 2007 The Electrochemical Society.