Modulation of electronic properties and Schottky barrier in the graphene/GaS heterostructure by electric gating

In this work, the structure, electronic properties, and the Schottky barrier of the van der Waals heterostructure (vdWH) based on graphene and gallium sulfide (GaS) have been theoretically considered using density functional theory. We found that the graphene/GaS vdWH keeps the extraordinary intrinsic properties of both the graphene and GaS monolayer. Moreover, an n-type Schottky contact with a small Schottky barrier of 0.51 eV was formed in the ground state of the heterostructure. Especially, our results demonstrated that applying an electric gating can tune effectively the Schottky barrier and contact types. The transformations from the n-type Schottky contact to the p-type one and from the Schottky to the Ohmic contacts were observed in the vdWH under electric gating. These results propose a great potential for the van der Waals heterostructure in future nanoelectronic and optoelectronic devices. © 2018 Elsevier B.V.