Interface effect on electronic and optical properties of antimonene/GaAs van der Waals heterostructures

Abstract

The integration of two-dimensional (2D) materials with III–V semiconductor surfaces leads to the formation of 2D/3D van der Waals (vdW) heterostructures without the constraint of lattice matching, which offers new opportunities to improve electronic and optoelectronic properties. Here we explore the structural, electronic, and optical properties of various potential Sb/GaAs heterostructures consisting of a Sb monolayer (i.e., antimonene) on GaAs(111) substrates by using first-principles calculations within the density-functional theory. Our results demonstrate that the vdW interaction is crucial for the stability of Sb/GaAs heterointerfaces, but the interfacial coupling strength and band-structure characteristics of the heterostructures are strongly affected by the interface structures. We find that all stable Sb/GaAs heterostructures exhibit a type-II band alignment and have relatively small band gaps (0.71–1.39 eV) as compared to those of the independent Sb monolayer and GaAs substrates. Moreover, the formation of Sb/GaAs vdW heterostructures can lead to the separation of carriers and a high optical absorption coefficient in the visible-light range, which makes Sb/GaAs heterostructures a potential candidate for optoelectronic devices, such as solar cells.