Two-dimensional Janus-In2STe/InSe heterostructure with direct gap and staggered band alignment

Experimental fabrications of two-dimensional (2D) Janus materials are drawing considerable attention due to their asymmetrical structure and versatile applications in various fields. Here, we design a novel 2D Janus-In₂STe/InSe van der Waals (vdW) heterostructure and theoretically demonstrate its dynamic stability, electronic structures, work function and optical absorption, considering the effects of stacking configurations, interlayer spacing and external electric field. The Janus-In₂STe/InSe vdW heterostructure presents the intrinsic natures of direct band structures (~1.23 eV), staggered band alignment and superb optical absorption(~10⁵) under ultraviolet zone. Intriguingly, the vertical strain and electric field can induce the transformation of direct-indirect band structure and staggered-straddling band alignment. All findings provides the physical mechanism of Janus- In₂STe/InSe vdW heterostructure, and indicates that Janus InSe-based vdW heterostructure has promising applications under ultraviolet fields.