Interface Engineering of Band Evolution and Transport Properties of Bilayer WSe2 under Different Electric Fields

The van der Waals coupling modulation is a crucial method for designing of the physical performance in bilayer transition-metal dichalcogenides. Here, we report the band evolution and quantum transport properties of twisted bilayer WSe2 under the approach of vertical electric fields by utilizing first-principles calculations. We find that the bandgap type of bilayer WSe2 can be transformed from indirect to direct by twisting two monolayers. The external electric field can enable the bilayer WSe2 under six twist angles to achieve a semiconductor to metal transition. Especially, the stacking structures of 0 degrees and 60 degrees show transport anisotropy, and the transport performance in the zigzag direction is slightly better than that in the armchair direction. Moreover, the transport performance of the case with twisted 60 degrees is better than that of 0 degrees regardless of the edge direction, when an external electric field is applied. Our results are conducive to the design and application of future WSe2-based microelectronics and optoelectronic devices.