SURFACE EVOLUTION OF N-TYPE CDTE IN ACIDIC MEDIUM IN THE PRESENCE OF CE4+ IONS

In this work the evolution of the surface chemistry ofCdTe by immersion in 2 M H2SO4 solution containing Ce4+ ions is presented. Ce4+ ions ate reduced by injecting a hole in the valence band of CdTe. Therefore, at rest potential an oxidation current appears that compensates this reduction. CdTe is etched at stationary etching rates in the experimental conditions used in this work. its oxidation presents some specific features, closely associated with the presence of a superficial film rich in tellurium. Electrochemical techniques alone do not allow full characterization of the superficial film. However, with the addition of X-ray photoelectron spectroscopic analysis, the layer is chemically characterized and the electrochemical results can be better interpreted.