Tailoring electronic properties and Schottky barrier in sandwich heterostructure based on graphene and tungsten diselenide

Graphene based two-dimensional layered materials are attracting wide attention both experimentally and theoretically and show many superior properties that individual layers may not hold. In this work, we study theoretically the electronic properties of the graphene/WSe 2 van der Waals heterobilayer using the first-principle calculations. Our results demonstrate that the intrinsic electronic properties of graphene and WSe 2 monolayer are quite well preserved due to the weak van der Waals interactions. We find that the graphene/WSe 2 heterobilayer forms a p-type Schottky contact with the Schottky barrier height of 0.60 eV and shows a good thermoelectric material with high Seebeck coefficient at room temperature. Moreover, the p-type Schottky contact of the graphene/WSe 2 heterobilayer can be tailored by inserting WSe 2 monolayers to form graphene/WSe 2 /WSe 2 and WSe 2 /graphene/WSe 2 heterotrilayers or by applying electric field perpendicular to the heterobilayer. The p-type Schottky barrier decreases with the insertion of the WSe 2 layers, whereas it can be transformed to the n-type one when the negative electric field of −1.5 V/nm is applied. The results reveal the physical nature of the van der Waals heterostructures based on graphene and other two-dimensional transition metal dichalcogenides, which are helpful in providing a route to design graphene-based high-performance optoelectronic nanodevices, such as Schottky diodes and interlayer tunneling field-effect transistors. © 2019 Elsevier B.V.