Structural and Optical Properties of Lead Iodide Thin Films Prepared By Vacuum Evaporation Method


Structural and optical properties were studied as a function of films thickness forthermally evaporation PbI2 films. X-ray diffraction analysis confirmed that PbI2films are polycrystalline having hexagonal structure. The optical absorption dataindicate an allowed direct transmission with optical energy gap varies continuouslyfrom ( 2.15eV to 2.33eV) . The energy gap shows thickness dependence, whichcan be explained qualitatively by a thickness dependence of grain size through thedecrease of the grain boundary barrier height with grain size. The low fluctuationin energy gap indicates that the grain size is quite small, which is finding inagreement with AFM results.