Strain Engineering and Electric Field Tunable Electronic Properties of Janus MoSSe/WX2 (X=S, Se) van der Waals Heterostructures

Using first-principles calculations, the electronic properties of Janus MoSSe/WX2 (X=S, Se) van der Waals (vdW) heterostructures are investigated. The results show that MoSSe/WS2 and MoSSe/WSe2 heterostructures have type-II and type-I band alignments with indirect band gaps of 1.50 and 1.52 eV, respectively. The electronic properties of MoSSe/WX2 vdW heterostructures can be tuned by an electric field and mechanical strain. A band alignment transition occurrs with the applied electric field, and the band gap changes. A type-II to type-I band alignment transition occurrs in the Janus MoSSe/WX2 heterostructure with a large strain. The band characteristics of MoSSe/WSe2 are sensitive to the electric field and mechanical strain. A positive electric field (from the bottom WX2 to the Janus MoSSe) induces an indirect-to-direct band gap transition in the MoSSe/WSe2 heterostructure. This work suggests that the Janus MoSSe/WX2 heterostructures have tunable electronic properties, making them promising candidates for nanoscale device applications.