Graphene/g-C2N bilayer:gap opening, enhanced visible light response and electrical field tuning band structure

Abstract: Opening up a band gap of the graphene and finding a suitable substrate are two challenges for constituting the nano-electronic equipment. A new two-dimensional layered crystal g-C2N (Nat. Commun. 2015, 6, 1--7) with novel electronic and optical properties can be effectively synthesized via a wet-chemical reaction. And g-C2N can be used as a suitable substrate to open the band gap of graphene as much as 0.239 eV, which is large enough for the band gap opening at room temperature. The physics behind the band gap opening is that g-C2N substrate can produce the inhomogeneous electrostatic potential over the graphene layer. The imposition of external electrical field can tune the band gap of the hybrid of graphene/g-C2N effectively from the semiconductors to the metal. The hybrid graphene/g-C2N displays an enhanced optical activity compared with the pure g-C2N monolayer.