2D multifunctional SiAs2/GeAs2 van der Waals heterostructure

The structural and electronic properties of two-dimensional (2D) SiAs2/GeAs2van der Waals heterostructure (vdWH) and its applications are investigated by combing first-principles calculations and Silvaco Atlas simulations. The stable SiAs2/GeAs2vdWH exhibits an indirect bandgap of 0.99 eV in type II band alignment for light detection and energy harvesting. The vdWH can exhibit a direct bandgap up to 0.66 eV by applying an appropriate electric field (Eext). Due to theEextinduced charge redistribution, its band alignment can be transformed from type II to type I for light-emitting. Further simulation shows that the band alignment of SiAs2/GeAs2vdWH can be tuned back and forth between type II and type I by gate voltage in a single field-effect transistor for multiple functional applications. These results may be useful for applications of the SiAs2/GeAs2heterostructure in future electronic and optoelectronic devices.