First-principles study on graphene/WSi2N4 van der Waals heterostructure: Tuning the Schottky barrier

Achieving ohmic contact at the interface of the metallic electrode and semiconducting channel is essential to improve device performance. We investigate the electrical contact properties of the van der Waals graphene/WSi2N4 heterostructure with first-principles theory. The possibility of tuning the contact barrier height and type is studied by varying the external electric field (Eext) as well as the layer spacing. An n-type ohmic contact is attained at Eext < −0.5 V/Å, while a p-type ohmic contact is attained at Eext > +0.6 V/Å. An n- and p-type Schottky contact is obtained when the interlayer distance is smaller and larger than 3.2 Å, respectively. This discovery provides insights for designing novel nanoelectronic devices based on graphene/WSi2N4 vdW heterostructures.