The electronic and optical properties of Type-Ⅱ g-CN/GaGePS van der Waals heterostructure modulated via biaxial strain and external electric field

Based on the superior properties of g-CN and GaGePS monolayers, this paper investigates the optoelectronic properties of the g-CN/GaGePS van der Waals heterostructure under strain and external electric field modulation using density functional theory. The results show that g-CN/GaGePS heterostructure has a type II band alignment and possesses an indirect band gap of 0.986eV, which exhibits enhanced absorption in the visible and ultraviolet range. Under the application of a biaxial strain of 7 %, the g-CN/GaGePS heterostructure undergoes a transition from type II to type I. Furthermore, the electric field not only modulates the g-CN/GaGePS band gap, but also induces band alignment (type II to type Ⅰ) and an indirect gap to direct gap transition. The absorption in the visible range is enhanced by a positive electric field, whereas a negative electric field exerts the opposite effect. A negative electric field enhances UV range absorption. These results suggest that the g-CN/GaGePS heterostructure has prospective applications in optoelectronic devices.