Thin films of tin sulfoselenide (SnS0.5Se0.5) have been electrodeposited from an aqueous solution on tin oxide coated glass substrates by potentiostatic technique. XRD pattern of SnS0.5Se0.5 films showed polycrystalline nature and orthorhombic structure. The presence of Sn, S, and Se of the films were confirmed by XPS analysis. All films showed an indirect band gap. Surface morphological studies were carried out using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analyses. Mott-Schottky plots have been drawn (in the dark condition) to evaluate the semiconductor parameters which confirmed the p-type nature of the films. The photoelectrochemical behavior of the SnS0.5Se0.5 films was studied in the electrolyte containing 0.1 M (FeCl2/FeCl3) + 0.05 M H2SO4 and the results are reported. (C) 2003 Elsevier Science Ltd. All rights reserved.