An investigation into the effect of ionic species on the formation of ZnTe from a citric acid electrolyte

Cathodic electrodeposition of ZnTe film was carried out on Au/Cu substrate using three kinds of citric acid electrolytes, each with a different counter anion, i.e., sulfate, chloride, or nitrate ions, to investigate the anion species' influence on the morphology, composition and structure of the resulting electrodeposited ZnTe films. Both chloride and nitrate electrolytes gave crystalline ZnTe films with almost stoichiometric ZnTe composition under electrolytic conditions similar to those optimized previously for sulfate electrolyte. The mean crystallite size of the electrodeposited ZnTe films ranged from 13 to 37 nm. The effect of the ionic species on the crystallite size was also investigated. The degree of ZnTe(1 1 1) plane orientation of the films obtained from nitrate electrolyte was stronger than that of the films from sulfate or chloride electrolytes. High resolution SEM observations revealed different morphologies depending on the anion in the electrolytic solution.