CHARACTERIZATION OF PbI2 THIN FILMS PREPARED BY FASTVACUUM THERMAL EVAPORATION

[摘要] In this work, XRD and some optical parameters of porous PbI2 thin films were investigated. Various thicknesses of lead iodide thin films were prepared by fast thermal evaporation technique (TET). X-ray diffraction patterns showed diffraction peaks before and after annealing at the orientations (001), (002), (202), (003) and (220) at 2=12.6°, 25.4°, 38.8°, 41.6° and 52.2°, respectively. Scherrer analysis indicated that grain size extends from about 8 to 18 nm. Scan electron microscopy (SEM) revealed high porosity of PbI2 thin films. UV-vis spectroscopy and diffusive reflectivity have been used to calculate the optical bandgap. The two methods indicate that the PbI2 prepared by TET has a direct optical bandgap (about 2.5 eV) with Urbach tail width of the order 0.76 eV.

[学科分类] 生物技术

[关键词] Pbl2 thin films;Vacuum evaporation;Direct bandgap