Giant tunability in electrical contacts and doping via inconsiderable normal electric field strength or gating for a high-performance in ultrathin field effect transistors based on 2D BX/graphene (X = P, As) van der Waals heterobilayer

Electrical contacts arising at the van der Waals interface between boron pnictide (h-BP, h-BAs) and graphene monolayers have been systematically investigated using density functional theory. The electronic band structure of the individual monolayers is well preserved in the heterostructures constituted from them, indicating a weak van der Waals (vdW) interaction between them. BP monolayer is found to form n-type Schottky contact with a Schottky barrier height (SBH) of 0.4 eV in BP/graphene van der Waals heterostructure (vdWH), whereas a small p-type SBH of 0.16 eV occurs at BAs/graphene vdWH. The SBHs obtained for BX/graphene are lower than that of other transition metal dichalcogenide based graphene vdWH and electrical properties are found to be sig-nificantly tunable/transformable via small applied electric field of +/- 0.15 V/angstrom. These insightful results will motivate experimentalists and technologists to design high performance graphene-based hybrid field-effect transistors (FET). Also, the vdWHs are found to show significant robustness, structural integrity and flexibility. The bending modulus of BP (As)/graphene is found to be lower than that in graphene/MoS2. The graphene/h-BN vdWH has been experimentally studied, while the thin films of h-BP have been recently synthesized; thereby substantiating the experimental feasibility in building up the heterostructures proposed in this work.