Mechanistic studies on the electrodeposition of ZnTe

Voltammetry on glassy carbon and steel rotating disk electrodes (RDE) was used to investigate the plating of ZnTe, an Important material for heterojunction solar cells, by codeposition from acidic (pH 2 to 5) aqueous solutions containing Zn2+ and TeO2. The influence of pH, TeO2, and Zn2+ concentration, and mass transfer under controlled conditions is shown. From RDE at various [Zn2+] and [TeO2] we can conclude that the plating of ZnTe is controlled by mass transfer of the tellurium precursor, and that Zn2+ adsorption does not play a major role. The limitations of plating due to side reactions at pH (<3) and limited solubility of TeO2 at high pH (>3) can be overcome by using pH 4.5 and a special precursor. Optimized plating conditions and use of elevated temperatures led to the formation of stoichiometric, well-crystallized material.