Cadmium selenide (CdSe) thin films have been electrodeposited on the titanium or ITO substrate in an electrolyte containing CdSO4 and H2SeO3 at pH = 2.50 and temperature 298 K. Influence of different deposition potentials on the surface morphology CdSO4 and H2SeO3 at pH = 2.50 and temperature 298 K. Influence of different deposition potentials on the surface morphology and crystal structure of CdSe films has been discussed. Compared with other deposition potentials (-0.65, -0.71 and -0.72 V versus SCE), the nearly stoichiometric CdSe nanocrystalline films with smaller grain sizes of 80 nm were obtained from 0.25 M CdSO4 + 0.25 mM H2SeO3 + 0.25 M Na2SO4 solution at deposition potential of -0.70 V versus SCE. X-ray diffraction, atomic force microscope and scanning electron microscope were used to measure structure and morphology of CdSe films. The results indicated that the electrodeposited films were the smooth, compact and uniform at deposition potentials of -0.70 V versus SCE. (C) 2004 Elsevier B.V. All rights reserved.