Tunable electronic structures and interface contact in graphene/C3N van der Waals heterostructures

Abstract

Graphene-based van der Waals heterojunctions can not only modulate the electronic properties of graphene but also retain the superior properties of the original monolayer. In this paper, the structure, electrical contact types, electronic and optical properties of Graphene/C3N van der Waals heterojunctions are systematically investigated based on first-principles calculations. We find that there is a p-type Schottky contact of only 0.039 eV in the Graphene/C3N van der Waals heterojunctions at the equilibrium state. The external electric field can adjust the interface contact type, from p-type to n-type schottky contact, or from p-type schottky contact to ohmic contact. The vertical strain not only opens a nonnegligible band gap of 360 meV at the Dirac cone of Graphene in Graphene/C3N van der Waals heterojunctions, but also modulates the band gap of C3N in the heterojunctions. Moreover, both the doping type and concentration of the carrier can be effectively tuned by the applied electric field and the vertical strain. The increase in carrier concentration is more pronounced by the applied electric field. Compared with the pristine monolayer Graphene and monolayer C3N, the optical response range and the light absorption rate of Graphene/C3N van der Waals heterojunctions are enhanced. Main absorption peak in the spectrum up to 106 cm-1. These results not only provide valuable theoretical guidance for the design of Schottky-based Graphene/C3N van der Waals heterojunctions devices, but also further explore the potential of heterojunctions for further applications in optoelectronic nanodevices and field-effect transistor devices.