lTHE COMPOSITION AND FORMATION MECHANISM OF ELECTRODEPOSITED CdSe FILMS

The cathodic deposition mechanism of CdSe films on T1 substrates was investigated using cyclic voltammetry and in-situ photocurrent mesurements XPS analysis showed that CdSe film composition depends on deposition potential, deposition time and concentrations of H2SeO3 in the bath, It was found that in 0.1mol.L-1 CdSO4 + 4mmol . L-1 H2SeO2 + 0.2mol . L-1 H2SO4, the deposits formed at potentials more positive than -0.50V are rich In Se, alternatively films rich in Cd are obtained at potentials more negative than -0.70V. The Se/Cd ratio of CdSe layers deposited at -0.68V approach to 1.1, but the content of Se in the deposits increases with. increasing H2SeO3 concentration. The results showed that the electrodeposition of CdSe follows two different mechanic corresponding to different deposition conditions. Modification of stoichiometry in CdSe films was also discussed.