Mechanical exfoliation and Raman spectra of ultrathin PbI2 single crystal

Abstract In this paper, we report the successful fabrication of ultrathin PbI2 single crystal by mechanical exfoliation method after the realization of graphene. The properties of samples were investigated by X-ray diffraction, atomic force microscopy and Raman scattering. The XRD spectrum indicates that PbI2 crystal has hexagonal crystalline pattern with 2H type crystal structure. The thickness around 10 nm about 15 layers of PbI2 single crystal verified by AFM was obtained. Five Raman bands with peaks at 73, 95, 111, 167, and 214 cm−1 are observed with 532 nm laser, while there are only four bands can be observed for laser 676.4 nm and 514.5 nm respectively. The results of ultrathin PbI2 single crystal will stimulate further theoretical calculations and experimental investigation of their fundamental properties and potential applications.