Strong interlayer hybridization in the aligned SnS2/WSe2 hetero-bilayer structure

Abstract

[EN] The combination of monolayers of different two-dimensional (2D) materials into van der Waals hetero-bilayer structures creates unprecedented physical phenomena, acting as a powerful tool for future devices. Understanding and exploiting these phenomena hinge on knowing the electronic structure and the hybridization of hetero-bilayer structures. Here, we show strong hybridization effects arising between the constitutive single layers of a SnS/WSe hetero-bilayer structure grown by chemical vapor deposition. Surprisingly, the valence band maximum position of WSe is moved from the K point for the single layer WSe to the Γ point for the aligned SnS/WSe hetero-bilayer. Additionally, a significant photoluminescence quenching is observed for the SnS/WSe hetero-bilayer structure with respect to the WSe monolayer. Using photoluminescence spectroscopy and nano-angle-resolved photoemission spectroscopy techniques, we demonstrate that the SnS/WSe heterostructure present a type-II band alignment. These findings directly answer many outstanding questions about the electronic band structure and the band offset of SnS/WSe hetero-bilayers for envisaging their applications in nanoelectronics.