Tuning electronic properties and contact type in van der Waals heterostructures of bilayer SnS and graphene

TL;DR

This study uses first-principles calculations to explore how external electric fields can tune the electronic contact types in van der Waals heterostructures of SnS and graphene, revealing potential for nanoelectronic device design.

Contribution

It demonstrates the ability to switch contact types in SnS/graphene heterostructures using electric fields, providing new insights into tunable nanoelectronic interfaces.

Findings

Ohmic contacts can be formed and tuned with electric fields.

Electric fields can convert Schottky contacts into Ohmic contacts.

Contact types influence the optical properties of heterostructures.

Abstract

Using first-principles calculations, we study the structural and electronic properties of the bilayer SnS/graphene, bilayer SnS/bilayer graphene (AA-stacked), bilayer SnS/bilayer graphene (AB-stacked) and monolayer SnS/graphene/monolayer SnS van der Waals (vdW) heterostructures. Electronic properties of all components of the vdW heterostructures are well preserved, which reflects the weakness of the vdW interaction. In the cases of bilayer SnS/graphene and bilayer SnS/bilayer graphene (AA-stacked), an Ohmic contact is formed which can be turned first into p-type and then into n-type Schottky contacts via application of an external electric field. Calculations show that an Ohmic contact is also formed at the interface of bilayer SnS/bilayer graphene (AB-stacked) heterostructure, but interestingly, by applying the perpendicular electric field a transition from semimetal/semiconductor contact to semiconductor/semiconductor one occurs which can enhance its optical properties. Alternatively, in the monolayer SnS/graphene/monolayer SnS vdW heterosructure, a p-type Schottky contact is established that changes into Ohmic contact under an applied electric field. Our results clearly indicate that the electronic properties of the vdW heterostructures can be tuned efficiently by external electric field, which is important in designing of new nanoelectronic devices.