Theoretical study of Schottky regulation of graphene/MoSe2 heterojunctions by non-metal doping

Abstract

The Schottky regulation mechanism of nonmetal-doped graphene/MoSe2 heterojunctions was investigated using a first-principles approach. Graphene and MoSe2 bonded with weak van der Waals forces to form a stable structure. The combination of graphene and MoSe2 still maintains their respective intrinsic properties and forms an n-type Schottky contact. Non-metal doping can effectively modulate the Schottky type and height of graphene/MoSe2 heterojunctions. B and P doping of MoSe2 transforms MoSe2 from a direct band-gap semiconductor to metal, and when combined with graphene to form a heterojunction, the heterojunction behaves as an ohmic contact.After N-doped MoSe2 combines with graphene to form a heterojunction, the Schottky type is converted from n-type to p-type. The doping of C and Si atoms reduces the direct band gap of MoSe2, and the doping of S increases the band gap of MoSe2 but does not have much effect on it. When C-, Si- and S-doped MoSe2 is combined with graphene to form a heterojunction, impurity energy levels appear in the conduction band and effectively reduce the band gap of MoSe2, resulting in a lower Schottky barrier.