Influence of citrate ions as complexing agent for electrodeposition of CuInSe2 thin films

The preparation of CuInSe2 thin films by electrodeposition is studied. The effect of sodium citrate (Na3C6H5O7) as complexing agent on the electrodepo sition of pure copper, indium, selenium and of their ternary alloy is empha sized. Cathodic shifts of the copper and selenium electrodeposition potenti als with increasing citrate concentration are observed. On the contrary, th e presence of citrate in the electrolyte does not change the indium electro deposition potential but improves its crystallinity. The surface morphology and the composition of the deposited films are characterized by scanning e lectron microscopy (SEM). The texture of the deposits and their composition s are analyzed by X-ray diffraction. The formation of CuInSe2 films with a chalcopyrite structure and good stoichiometry is observed.