Halogen atom-doped graphene/MoSe2 heterojunction Schottky barrier height modulation

Achieving lower Schottky barrier heights in logic devices remains a formidable challenge. In this paper, the effect of halogen atoms doping on the type and height of graphene/MoSe2 Schottky is investigated using density functional theory. For monolayer MoSe2, the doping of halogen atoms introduces impurity energy levels in the energy band and leads to a change in the position of the Fermi energy level. Graphene and MoSe2 bonding retains their respective intrinsic electrochemical properties and bond with weak van der Waals forces to form n-type Schottky contacts. The doping of halogen atoms effectively changes the Schottky type and height of graphene/ MoSe2. The Schottky type of heterojunctions doped with F, Cl, and Br atoms changes from n-type contacts to ohmic contacts. I and At atoms effectively reduce the Schottky barrier height of graphene/MoSe2. The disparity charge density indicates that the electrons in graphene are transferred to MoSe2, forming a built-in electric field pointing from graphene to MoSe2. After the doping of halogen atoms, the interlayer charge transfer between graphene and MoSe2 is significantly reduced, and the Fermi energy level appears to be shifted downward, which eventually leads to the reduction of the Schottky barrier height.