Tunable Schottky barrier in a graphene/AlP van der Waals heterostructure

The controllable modulation of the electronic properties of two-dimensional van der Waals (vdW) heterostructures is crucial for their applications in the future nanoelectronic and optoelectronic devices. In this paper, the electronic properties of a graphene/AlP heterostructure are theoretically studied by first-principles calculation. The results show that due to the weak vdW interaction between graphene and the AlP monolayer, both the Dirac semi-metallic properties of graphene and the semiconductivity properties of monolayer AlP are well retained. The graphene/AlP heterostructure forms a 0.41 eV p-type Schottky contact, and the barrier height and contact type can be successively controlled by the applied external electric field and vertical stress. When the applied electric field exceeds -0.5 V angstrom(-1), the heterostructure interface changes from a p-type Schottky contact to an n-type Schottky contact. When the applied electric field exceeds 0.4 V angstrom(-1) or the interlayer spacing is less than 3.1 angstrom, the interface contact type changes to Ohmic contact. These results indicate that the graphene/AlP heterostucture behaves as tunable Schottky barrier for potential applications in nano-devices.