Gallium arsenide (GaAs) is one of the important materials used for the fabrication of light emitting diodes, solar cells, microwave devices, etc. In the present work, electrodeposition of GaAs was successfully carried out potentiostatically from an aqueous solution mixture of gallium chloride (GaCl3) and arsenic oxide (As2O3). The optimum deposition potential, pH and bath temperature to synthesize GaAs thin films are found to be -0.8V versus SCE, 2.0 +/- 0.1 and 60 degrees C, respectively. The effects of solution pH, bath temperature and deposition potential on the gallium content of GaAs films are studied. Photoelectrochemical (PEC) solar cells using n-GaAs photo-anode in a polysulphide electrolyte is constructed and I-V, C-V studies are carried out. Various semiconductor parameters such as, flat-band potential, band bending, donor,density, depletion layer width are evaluated and the results are discussed. (c) 2006 Elsevier B.V. All rights reserved.