Modulation of the electronic properties of two-dimensional MoTe2/WSe2 heterostructure by electrical field

The structure and electronic properties of two-dimensional MoTe2/WSe2 van der Waals heterostructure under external electric field have been investigated by first-principles calculation. The interlayer distance between MoTe2 and WSe2 is 3.613 angstrom and the binding energy per unit is -0.183eV, which indicated that MoTe(2 )is bound to WSe2 via van der Waals interaction. The interlayer distance can be modified by external electric field and the band gap of MoTe2/WSe2 heterostructure continuously decreases with increasing external electric field, eventually a transition from semiconductor to metal is observed, particularly, the band alignment of the MoTe2/WSe2 heterostructure can be effectively tuned from intrinsic type-II to type-I. Applying external electric field along +z direction and -z direction has different effects on the band gap due to the intrinsic spontaneous polarization in MoTe2/WSe2 heterostructure. Our study indicates that the external electric field can significantly tune the band offsets and modify the band alignment between MoTe2 and WSe2. The present study would be helpful for application of such transition-metal dichalcogenides heterostructures in nano- and optoelectronics.