Reconfigurable band alignment of SWSe/h-BP heterostructures for photoelectric applications

The integration of two-dimensional (2D) materials into van der Waals heterostructures (vdWHs) is regarded as an effective strategy for fabricating multifunctional devices. Herein, the effects of the vertical electric field and biaxial strain on the electronic, optical and transport properties of SeWS (SWSe)/h-BP vdWHs are systematically investigated using density functional theory calculations. The study shows that electric fields and biaxial strain can modulate not only the band gap but also the band alignment to produce multifunctional device applications. The SWSe/h-BP vdWHs can be used as highly efficient 2D exciton solar cells with a power conversion efficiency of up to 20.68%. In addition, the SWSe/h-BP vdWHs present a significant negative differential resistance (NDR) with a peak-to-valley ratio of 1.12 (1.18). The present work may provide a direction for tunable multiple-band alignments in SWSe/h-BP vdWHs and help achieve multifunctional device applications.