Modulating the electronic properties of monolayer MoS₂ through heterostructure with monolayer gray arsenic

Two-dimensional layered materials attract much attention due to their outstanding intrinsic properties and wide applications. In this work, the mechanical and electronic properties of monolayer MoS₂ on monolayer gray arsenic (g-As) substrates are studied by first-principles calculations. Results indicate that both g-As and MoS₂ undergo small corrugations when monolayer MoS₂ is bonded to g-As. The lowest binding energies (~-0.05 eV) and the electronic structures are almost independent of the atomic arrangement. But the indirect band gap of g-As/MoS₂ heterostructure enlarges with increasing the interlayer distance. Moreover, the valence band maximum consists of π-like states rather than σ states upon the formation of g-As/MoS₂ heterostructures. Interestingly, complete electron-hole separation is found in the g-As/MoS₂ heterostructures, which can facilitate the application of MoS₂ on photoelectric device. In addition, the work function of monolayer MoS₂ shifts down upon the g-As/MoS₂ heterostructures formation since a certain charge transfer is found between MoS₂ and g-As even though the interlayer interaction is very weak. Our findings provide a detailed understanding of the nature physical properties of g-As/MoS₂ heterostructures, and suggest a simple way to fabricate and improve the application of monolayer MoS₂ in nanodevices.