Optical and structural properties of lead iodide thin films prepared by vacuum evaporation method

Thermally processed lead iodide (PbI2) thin films were prepared by the vacuum evaporation method in a constant ambient. Measured thickness of the film was verified analytically from the optical transmittance data in a wavelength range between 300 and 1600 nm. From the Tauc relation for the non- direct inter band transition, the optical band gap of the film was found to be 2.58 eV for film thickness 300 nm. X-ray diffraction analysis confirmed that PbI2 films are polycrystalline, having hexagonal structure, The low fluctuation in Urbach energy indicates that the grain size is quite small. The present findings are in agreement with the other results. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.