Effect of laser energy on the properties of nanostructured lead iodide film prepared via pulsed laser deposition technique

The effect of laser energy density on the optical, structural and electrical properties of lead iodide PbI2 film prepared by laser deposition technique was studied. X-ray diffraction XRD results revealed that the PbI2 films deposited at laser energy density smaller than 3.5 J/cm2 are polycrystalline in nature with preferred orientation along (001) plane, while the film deposited at 3.5 J/cm2 was amorphous. The thickness and deposition rate of the film was found to be increased with laser energy density. The optical energy gap of PbI2 film was in the range of (2.5-2.65) eV. SEM investigations showed that the deposited films are dense and have a homogeneous structure and the average grain size increases from 25 to 55 nm as laser energy density increases from 2 to 3.5 J/cm2. The film surface composed of aggregated grains and particulates. Energy dispersive x-ray illustrated the film deposited at 2 J/cm2 was stoichiometric and the films deposited at laser energy density >2 J/cm2 were off-stoichiometric. The electrical properties revealed that the deposited films were p-type and the electrical resistivity decreases from 9.2 × 104 to 1.49 × 104 Ω.cm when laser energy density increases from 2 to 3 J/cm2.The hole mobility of the film was found to increase with laser energy density. The dark and illuminated I-V characteristics of p-PbI2/n-Si heterojunctions were investigated as a function of laser energy density.