Morphological and structural evolution during thermally physical vapor phase growth of PbI2 polycrystalline thin films

PbI2 polycrystalline thin films have been prepared by using a thermally physical vapor phase growth in vacuum. X-ray diffraction measurement and atomic force microscope analysis show that the structural change of the films occurs depending on growth condition. The width of the Urbach tail of the films indicates that the disordered structure inside the grains changes relying on preparation condition. It is found that the structure of the films is sensitive to growth parameter. A microstructure evolution model with respect to grain orientation is developed to explain the morphological and structural variation process during the films growth.