First-principles calculations on strain and electric field induced band modulation and phase transition of bilayer WSe2 MoS2 heterostructure

Highlights: • Bandstructure of WSe₂MoS₂ heterostructure exhibits unusual response to both exterior strain and electric field. • The applied strain shows no direction-depended character for the modulation of bandgap of WSe₂MoS₂ heterostructure. • The electric field tuning processes strongly depends on the direction of the electric field. • WSe₂MoS₂ exhibits a typical type-II heterostructure, so the electron−hole pairs can be effectively spatially separated. A purposeful modulation of physical properties of material via change external conditions has long captured people's interest and can provide many opportunities to improve the specific performance of electronic devices. In this work, a comprehensive first-principles survey was performed to elucidate that the bandgap and electronic properties of WSe₂MoS₂ heterostructure exhibited unusual response to exterior strain and electric field in comparison with pristine structures. It demonstrates that the WSe₂MoS₂ is a typical type-II heterostructure, and thus the electron−hole pairs can be effectively spatially separated. The external effects can trigger the electronic phase transition from semiconducting to metallic state, which originates from the internal electric evolution induced energy-level shift. Interestingly, the applied strain shows no direction-depended character for the modulation of bandgap of WSe₂MoS₂ heterostructure, while it exists in the electric field tuning processes and strongly depends on the direction of the electric field. Our findings elucidate the tunable electronic property of bilayer WSe₂MoS₂ heterostructure, and would provide a valuable reference to design the electronic nanodevices.