Copper indium diselenide polycrystalline thin films of p-, i- and n-type electrical conductivity were grown using a one-step electrodeposition process in a single bath. The bulk structure and the stoichiometry of the layers were determined using X-ray diffraction and X-ray fluorescence. The material composition was correlated with the electrical conductivity type variation, detected by the photoelectrochemical cell. Atomic force microscopy analysis showed copper-rich films deposited at low cathodic potentials (0.6 V vs Ag/AgCl) are of spherical and granular morphology and the grain sizes were 0.3-0.5 mum, while stoichiometric CIS films deposited at 1.0 V vs Ag/AgCl have grain sizes of 0.1-0.4 mum. The initial studies of optoelectronic properties (V-oc J(sc) and FF) of the four-layer solar cell devices (glass/FTO/n-CdS/n-CIS/i-CIS/p-CIS/Au) are presented. (C) 2003 Elsevier B.V. All rights reserved.