Electric-field tunable electronic structure in WSe2/arsenene van der Waals heterostructure

The electronic properties of WSe2/arsenene van der Waals (vdW) heterostructure with an external electric field (Eext) are investigated by density functional theory (DFT). It is demonstrated that the WSe2/arsenene heterobilayer is a type-II vdW heterostructure, and thus electrons and holes are spatially separated. The WSe2/arsenene heterobilayer undergoes a transition from semiconductor to metal when subjected to an Eext. The positive and negative Eext have different effects on the band gap due to the spontaneous electric polarization in WSe2/arsenene heterostructure. The variation of band edges as a function of Eext provides further insight to the linear variation of the band gap. Moreover, the WSe2/arsenene vdW heterostructure experiences transitions from type-II to type-I and then from type-I to type-II with an increasing negative Eext. The present study would open a new avenue for application of ultrathin WSe2/arsenene heterobilayer in future nano- and optoelectronics.