Effect of strain on electronic properties of tri-layer MoS2/h-BN/graphene van der Waals heterostructures

Abstract

The two-dimensional materials have grabbed the attention of researchers because of their high functionality and widely controllable properties. Due to the dimensionality reduction, the external factors have a significant influence on their properties. The density functional theory calculations have been performed on the heterostructures of single-layer graphene (G), boron nitride (BN) and molybdenum disulfide (MoS2) to investigate the alteration in their electronic properties. Our calculations predict that electronic properties such as bandgap, work function, Schottky barrier height and tunnelling barrier probability can be modulated by applying mechanical strain. The application of strain resulted in a band gap opening of about 1 eV in trilayer heterostructures. At low values of strain, heterostructures maintained a low resistance ohmic contact. At −9% strain, the p-to-n-type transition of Schottky contact was observed indicating the flow of electrons from semiconductor to metal. The MoS2 monolayer was found to be more electron deficient and exhibited a greater charge accumulation. MoS2/BN/G heterostructure can be used for the fabrication of capacitive devices. Whereas BN/G/MoS2 and BN/MoS2/G heterostructures can act as potential candidates for trilayer Schottky devices due to the presence of low-barrier metal-semiconductor junction.