Fe3+ doped delta-Bi2O3 thin films were prepared by sol-gel method on quartz glass substrate at room temperature and annealed at 800 degrees C. The thin films were then characterized for structural, surface morphological, optical and electrical properties by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption measurements and d.c. two-probe, respectively. The XRD analyses revealed the formation delta-Bi2O3 followed by a mixture of Bi25FeO40 and Bi2Fe4O9. SEM images showed reduction in grain sizes after doping and the optical studies showed a direct band gap which reduced from 2.39 eV for pure delta-Bi2O3 to 1.9 eV for 10% Fe3+ doped delta-Bi2O3 thin film. The electrical conductivity measurement showed the films are semiconductors. (c) 2009 Published by Elsevier B.V.