Investigation on electronic properties modulation of vdW GaN/WSe2 heterostructure by electric field

Abstract

In this paper, we designed two van der Waals (vdW) GaN/WSe2 heterostructures based on the GaN and WSe2 monolayers. And then we further investigated the effect of the external electric field on electronic properties of the more stable GaN/WSe2 vdW heterostructure by first-principle calculations. Results show that without external electric field, the GaN/WSe2 is a typical type-I band alignment heterostructure. But both the VBO and CBO are smaller than 1 eV, which limits their application in electric devices. So we further adopt an external electric field to adjust the electronic properties of the heterostructure. Results show that when applying an external electric field of [Formula: see text] V/Å, the band alignment of GaN/WSe2 heterostructure changes from type-I to type-II, and the electrons and holes are separated into different layers. Then the recombination of the holes and electrons is blocked and the lifetime of photo-induced carriers can be prolonged. To understand the inherent physical mechanism, the variation trends of the band gap and band offset as the change of external electric field were discussed. Results show that the location and contribution factors of conduction band minimum (CBM) and valence band maximum (VBM) caused by external electric field are the main factors causing this change in the heterostructure.