First principles study on the electronic properties and Schottky barrier of Graphene/InSe heterostructure

Graphene-based van der Waals heterostructures by stacking graphene on other two-dimensional materials have recently attracted much attention due to their extraordinary properties and greatly extend the applications of the parent materials. By means of the density functional theory from first-principles calculations, in this work, the electronic properties and Schottky contact of the Graphene/InSe heterostructure, together with the effect of strain, are investigated systematically. Our results show that in the graphene/InSe heterostructure, graphene is very weakly bound to the InSe monolayer. Furthermore, we find that due to the sublattice symmetry breaking, a tiny band gap of 5 meV is opened in the graphene/InSe heterostructure, making it suitable for applications in electronic and optoelectronic devices. Moreover, we also find that the n-type Schottky contact is formed in the graphene/InSe heterostructure with a very small Schottky barrier height of 0.05 eV. The Schottky barrier height as well as Schottky contact types in the graphene/InSe heterostructure could be controlled by vertical strain applied perpendicularly to the heterostructure. When the interlayer distance between graphene and the topmost InSe monolayer is smaller than 2.40 Å one can observe a transformation of the Schottky contact of the graphene/InSe heterostructure. Our results may provide helpful information for designing novel high-performance graphene-based van der Waals heterostructures and explore their potential applications in future nanoelectronic and optoelectronic devices.