Controllable Schottky barriers and contact types of BN intercalation layers in graphene/MoSi2As4 vdW heterostructures via applying an external electrical field

Abstract

Graphene-based van der Waals (vdW) heterostructures have opened unprecedented opportunities for various device applications due to their rich functionalities and novel physical properties. Motivated by the successful synthesis of a MoSi₂N₄ monolayer (Science, 2020, 369, 670), in this work by means of first-principles calculations we construct and investigate the interfacial electronic properties of the graphene/MoSi₂As₄ vdW heterostructure, which is expected to be energetically favorable and stable. Our results show that the graphene/MoSi₂As₄ heterostructure forms an n-type Schottky contact with a low barrier of 0.12 eV, which is sensitive to the external electric field and the transformation from an n-type Schottky contact to a p-type one can be achieved at 0.2 V Å⁻¹. The small effective masses and strong optical absorption intensity indicate that the graphene/MoSi₂As₄ heterostructure will have a high carrier mobility and can be applied to high-speed FET. Importantly, we also show that the opening band gap can be achieved in the graphene/BN/MoSi₂As₄ heterostructure and the type-I band alignment can transform into type-II under an external electric field of −0.2 V Å⁻¹. These findings demonstrate that the graphene/MoSi₂As₄ heterostructure can be considered as a promising candidate for high-efficiency Schottky nanodevices.