Gated BP/MoS2 Heterostructure with Temperature Enhanced Photocurrent

Two-dimensional van der Waals heterostructures offer versatile platforms for multifunctional optoelectronic devices. In this work, we study the electrical transport and the photoresponse in BP/MoS2 heterostructures made of multi-layer black phosphorus (BP) exfoliated over CVD-grown monolayer molybdenum disulfide (MoS2) with Cr contacts. The heterostructures show good rectification and a dominant n-type behavior under a back-gate voltage. The exposure to light reveals a high photoresponse with photocurrent enhanced by the rising temperature. The BP/MoS2 devices can be operated over a wide range of temperatures, either below or above room temperature. An energy band model that considers a type II BP/MoS2 heterojunction between two back-to-back Schottky junctions, at the Cr/BP and Cr/MoS2 interfaces, is proposed to explain the experimental results.