EFFECTS OF THERMAL AND CHEMICAL TREATMENTS ON THE COMPOSITION AND STRUCTURE OF ELECTRODEPOSITED CUINSE2 THIN-FILMS

Cu1+/-xIn1+/-ySe2+/-z thin films within a wide composition range have been obtained by a one-step electrodeposition method onto molybdenum substrates. These films were then submitted to different postdeposition treatments: annealing in argon atmosphere and/or chemical etching in a 0.5M KCN solution. The as-grown and treated samples were examined by x-ray diffraction for determination of crystalline quality and by chemical analysis for composition. Annealing improves the crystallinity of electrodeposited films; the effective grain size increased as the annealing temperature increased. Chemical etching produces significant changes in the film composition, the aqueous KCN solution dissolves secondary phases of copper selenides that have been detected in the samples. Depending on the sequence of annealing and chemical treatments, the resulting thin films exhibit different characteristics.