Survey of Tetragonal Transition Metal Chalcogenide Hetero‐Bilayers for Promising Photocatalysts

Abstract

AbstractThe formation of van der Waals (vdW) hetero‐bilayers have been emerging as unique structures to improve the performance of 2D layered nanomaterials for next‐generation photocatalysts. In this work, first‐principles calculations are employed to study the electronic and optical properties of a variety of tetragonal transition metal chalcogenide hetero‐bilayers. It is found that there are three stable semiconductor/semiconductor vdW hetero‐bilayers, and twenty‐one stable semiconductor/conductor vdW hetero‐bilayers. It is revealed that ZnS/ZnSe and ZnSe/ZnTe hetero‐bilayers possess a special band characteristic that is favorable for reducing the carrier recombination. In semiconductor/conductor hetero‐bilayers, the band edges of semiconductor are tuned via Schottky barrier, including p‐type and n‐type Schottky barrier. This work suggests that all hetero‐bilayers have an enhanced optical absorption within the visible light region, leading to more efficient solar energy harvesting. Based upon the theoretical calculations, tetragonal transition metal chalcogenide hetero‐bilayers will be great candidates as high performance photocatalysts for solar water splitting, as well as many other optoelectronic applications.