First principle study on interfacial interaction of black phosphorus and CsBr vdW heterostructure

Abstract

Two dimensional crystalline materials have attracted much attentions due to the establishment of heterostructure that can adjust their electrical and optical properties, and have potential applications in lasers, light-emitting diodes, solar cells and high mobility transistors. And the interface engineering is an effective route to tune structural and electrical properties in semiconductor heterostructures. In this study, the electronic structure, charge transport and optical properties of monolayer caesium bromide and black phosphorus (CsBr/BP) heterostructure are calculated by the first principle based on density functional theory (DFT). It was found that the characteristics of electronic band structures of the monolayer CsBr and BP remain in the heterostructure, and the effective mass and carrier mobility are highly anisotropic. When the heterostructure is uniaxially stretched, the mobility of electron is greater than that of the hole, while the biaxial stretching is just the opposite, the mobility of hole is greater than that of the electron. In addition, compared with the CsBr monolayer, the light absorption of the heterostructure is significantly enhanced, especially in the infrared, indicating that the CsBr/BP heterostructure can be well applied to photovoltaic devices in the future.