Electronic properties of MoS₂ sandwiched between graphene monolayers

The effect of an electric field on the electronic properties of a MoS2 monolayer between two graphene sheets (G/MoS2/G) is investigated within the framework of density functional theory. We show that the positive and negative electronic field applied in the direction perpendicular to the G/MoS2/G superlattice significantly modifies the electronic structure of the whole system, which can allow to control the values of the energy gap. It is shown that the energy dispersions are nearly linear in the vicinity of the Fermi level with and without external field. We elucidate the mechanism for the gap tuning by examining the projected density of states of C atoms and charge redistribution within graphene and charge transfer between graphene and MoS2 layers driven by the electric field. These findings are a useful complement to experimental studies of the G/MoS2/G system and provide a theoretical explanation for the extraordinary performance of this superlattice for fast speed and high on-off switching transistor.