Ohmic contact in graphene and hexagonal III-V monolayer (GaP, GaAs, InP, and InAs) van der Waals heterostructures: Role of electric field

To obtain Ohmic contact on the metal/semiconductor interface is desirable for optimizing the nanoelectronics' performance. We systematically investigate how the applied electric field affects the interface contacts on the graphene and low-buckling hexagonal III-V monolayer (GaP, GaAs, InP, and InAs) vdW heterostructures using the first-principles methods. The energy favorable vdW heterostructures have the metal group-III (Ga, In) atom closer to graphene and narrow p-type Schottky barriers of 0.05∼0.40 eV. The p-type Schottky contacts of the Gr/GaAs, Gr/InP, and Gr/InAs vdW heterostructures would transform to n-type under negative electric fields of −0.35∼−0.54 V/Å. Inspiringly, successful realization of p-type Ohmic contacts has occurred under positive electric fields of 0.1∼0.4 V/Å for all the Gr/III-V vdW heterostructures.