Tunable band offset in black Phosphorus/ReS2 van der Waals heterostructure with robust direct band and inherent anisotropy

Two dimensional materials based van der waals (vdW) heterostructures have attracted much interest recent years, due to their outstanding performance in optoelectronic and electronic devices. In this work, Black phosphorus (BP)/ReS2 vdW heterostructure was proposed and systemically investigated by ab-initio methods. BP/ReS2 system overcomes the drawback of indirect band existed in most of previous reports, and naturally forms a robust direct band semiconductor with type II band offset. Moreover, the system simultaneously possesses interesting anisotropy for optical and transport properties. The anisotropically optical absorption window covers wide range from infrared to the green light, and current of armchair direction is more than 2 orders higher than that of zigzag direction. In addition, the band offset and gap value can be effectively manipulated by applying electric field and regulating layer number of BP. Our investigation suggests BP/ReS2 vdW heterostructure shows great potential in novel optoelectronic and electronic devices of high quantum efficiency.