Electrodeposition of CdTe thin films on Te-modified polycrystalline gold substrates

A novel two-step approach for the cathodic electrodeposition of CdTe films, based on the initial electrochemical modification of polycrystalline gold substrates with elemental tellurium, is described. This Te-modified Au electrode is subjected to electroreduction (to generate Te2− species) in a separate, Te-free medium containing Cd2+ species. In situ precipitation results in the formation of a CdTe semiconductor film. For this two-step approach to work, the electroreduction of Cd2+ species will have to be shifted to more negative potentials past the Te0 → Te2− conversion regime. This was accomplished in the present study by complexation of Cd2+ species with ethylenediaminetetraacetic acid (EDTA). The CdTe films thus obtained were characterized by linear sweep voltammetry, electrochemical quartz crystal microgravimetry, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and photoelectrochemical experiments.