Interfacial properties of van der Waals lead iodide/graphene heterostructure

초록

van der Waals (vdW) type heterostructures based on two-dimensional (2D) layered crystals are attractive for various applications including electronics, optoelectronics, and spintronics owing to their exceptional structure-dependent properties. Lead iodide (PbI2), a vdW-type crystalline material is a promising candidate for photodetector applications. Especially, an enhanced photodetecting performance is expected from PbI2/graphene vdW heterostructure, relative to the isolated PbI2 film. It is of particular importance to prepare PbI2/graphene heterostructure in controllable manner to maximize the device capability. Here, we demonstrate selective PbI2 growth on graphene monolayers via chemical vapor deposition method. Systematic comparison of PbI2 domain morphologies grown on various substrates coupled with conductive AFM measurement suggests that the interfacial energy between the substrate (i.e., graphene) and PbI2 plays a key role in the fabrication of vdW heterostructure. This result provides fundamental perspective for the optimization of vdW heterostructure fabrication.