Band structure engineering in 2D BA2PbI4/InSe perovskite heterostructures and superlattices

Periodic stacking of two van der Waals materials enables the realization of superlattice structures with artificial design of band structure. Two-dimensional perovskites offer structural flexibility for engineering of band structure that can result in superlattice structures. Here, InSe/BA2PbI4 perovskite heterostructure and superlattice are explored by first principles calculation. Both the heterostructure and superlattice show a similar direct bandgap structure. As the concentration of VBA defects increases, the bandgap of the heterostructure and superlattices generally increase in different manners due to different interfacial interaction. The introduction of VI defects leads to the formation of a type-I band alignment, contrasting with the type-II band alignment resulting from VBA defects. These findings offer valuable insights into the defect-driven modulation of electronic properties in semiconductor superlattices and heterostructures, providing opportunities to tailor them for various optoelectronic applications.