Interface‐Dependent Electronic Structure and Optical Properties of Staggered Al₂STe/Ga₂STe van der Waals Heterostructures

Abstract

2D Janus monolayers and van der Waals heterostructures (vdWHs) exhibit fascinating physical properties because of the destruction of symmetry. The interface‐dependent electronic and optical properties of vdWHs constructed by Janus Ga2STe and Al2STe are explored. The results reveal that all interfaces vdWHs exhibit staggered (type‐II) band alignment. Specifically, the S/Te and Te/Te interfaces vdWHs are indirect bandgap semiconductors, while the S/S and Te/S interfaces vdWHs are direct bandgap semiconductors. The staggered band alignment promotes the electron transfer between the donor and acceptor in vdWHs, and the power conversion efficiency (PCE) of the Te/Te interface vdWH is as high as 25.34%. Furthermore, both S/Te and Te/Te interfaces vdWHs can provide suitable photocatalytic performance for water splitting under pristine conditions. By applying biaxial strain, S/S and Te/S interfaces vdWHs can be used as a photocatalyst. Under the compressive strain of 1%, the PCE of Te/Te reaches 28.68%. Based on the G0W0 + Bethe–Salpeter equation, different interfaces vdWHs exhibit different landscapes of intralayer exciting or interlayer exciting. The revealed type‐II band alignment, strong optical absorption, and superior PCE of the Al2STe/Ga2STe vdWHs imply that these new proposed materials have broad application prospects in optoelectronic devices such as excitonic solar cells.

Two-dimensional Janus X2STe (X = B, Al) monolayers: the effect of surface selectivity and adsorption of small gas molecules on electronic and optical properties

“…2D aluminum-based materials have attracted significant interest due to their unique physico-chemical properties and wide range of potential applications. 40 Their exceptional electrical, optical, mechanical, and thermal properties, as well as their high surface-tovolume ratio, make these materials very versatile and have many possible applications in fields as diverse as electronics, optoelectronics, and energy storage. [41][42][43] The application of two-dimensional aluminum-based materials has the potential to yield manufacturing processes that are environmentally sustainable and economically efficient.…”

“…The majority of these studies have adopted a more theoretical approach. 2D aluminum-based materials have attracted significant interest due to their unique physicochemical properties and wide range of potential applications [40]. Their exceptional electrical, optical, mechanical, and thermal properties, as well as their high surface-to-volume ratio, make these materials very versatile and have many possible applications in fields as diverse as electronics, optoelectronics, and energy storage [41][42][43].…”