Tunable Electronic and Optical Properties of AlSb/In₂Te₂Se van der Waals Heterostructure via Ferroelectric Substrate

The integration of ferroelectric materials into van der Waals heterostructures (vdW HSs) has emerged as a promising strategy for engineering electronic and optical properties, enabling advanced optoelectronic applications. In this work, we systematically investigate the influence of ferroelectricity on the electronic structure and optical characteristics of two-dimensional (2D) AlSb by using ab initio calculations. By leveraging the intrinsic ferroelectric properties of In 2 Te 2 Se, we demonstrate that the out-of-plane polarization orientation critically modulates the band alignment, bandgap, and optical absorption in 2D AlSb. Two distinct polarization configurations are explored: a type-II band alignment (AlSb/In 2 Te 2 Se↑) for photovoltaic applications and a type-I alignment (AlSb/In 2 Te 2 Se↓) for light-emitting applications. Furthermore, biaxial strain engineering is employed to precisely tune the bandgap and optical responses, with compressive strain yielding a remarkable peak power conversion efficiency (PCE) of 21.37%. The strong interlayer coupling effects significantly enhance optical absorption. These findings underscore the critical role of ferroelectricity in tailoring the electronic and optical properties of AlSb/In 2 Te 2 Se vdW heterostructures, positioning them as highly versatile candidates for next-generation multifunctional optoelectronic devices.