Modulation of electronic structures of MoSe2/WSe2 van der Waals heterostructure by external electric field

By using first-principles calculations, we investigate the electronic structures of MoSe2/WSe2 van der Waals(vdW) heterostructure by applying external electric field(Eext) perpendicular to the layers. It is demonstrated that MoSe2/WSe2 heterostructure is a type-II vdW heterostructure. The band gap of MoSe2/WSe2 is significantly modulated by Eext, eventually a semiconductor-to-metal transition can be realized. The positive and negative Eext have different effects on the band gap due to the intrinsic spontaneous electric polarization in MoSe2/WSe2 heterostructure. Moreover, MoSe2/WSe2 heterobilayer experiences transitions from type-II to type-I and then to type-II under various Eext. The present study provides great application potential of ultrathin MoSe2/WSe2 heterostructure in future nano- and optoelectronics.