High detectivity and responsivity in black phosphorus/SnS ₂ heterostructure with broken-gap energy band alignment

Abstract

Abstract van der Waals heterostructures (vdWHs) based on atomically two-dimensional materials have gained extensive attention due to their great potential in the new era of next-generation optoelectronics. Most reported photodetectors exhibit type-II band alignment and their photodetection performance is often limited by either low photoresponsivity or high dark current. However, type-Ⅲ vdWHs with broken gaps are still very rare, which limits the development and application of two-dimensional (2D) materials in the fields of photodetector. Here, we demonstrate a highly sensitive black phosphorus (BP)/SnS 2 photodetector with type-III (broken-gap) band alignment. The dark current of BP/SnS 2 vdWH is greatly suppressed by high barrier at the junction and high photoresponsivity generated from high tunneling current when illuminated. The BP/SnS 2 vdWH exhibits both ultrahigh photodetectivity of 6.72 × 10 12 Jones and photoresponsivity of 295.3 A W −1 under the illumination of 365 nm light (0.53 mW cm −2 ). Our results provide an avenue for developing high performance optoelectronics and better understanding the underlying physics in the broken-band alignment systems.