Vertical WSe2/BP/MoS2 heterostructures with tunneling behaviors and photodetection

Abstract

Van der Waals heterostructures show potential in electronic and optoelectronic devices. However, most heterostructures were formed based on the combination of two kinds two-dimensional (2D) materials. It is interesting to investigate the heterostructures of three kinds of 2D materials with unique band structure for photodetection and tunneling. In this work, vertical stacked WSe2/black phosphorus (BP)/MoS2 heterostructure has been made. By tuning the middle layer BP thickness from thin to thick, the device can be regarded as tunneling transistor and photodetector. Throughout thin BP (9 nm) sandwiched, tunneling transistor is realized in WSe2/BP/MoS2 heterojunction with a high ∼μA level tunneling current. Temperature dependent electrical characteristics proved tunneling mechanism. Throughout thicker BP (20–30 nm) flake sandwiched, high-performance photodetector can be achieved. The large bandgap of WSe2 and MoS2 can further reduce the dark current to ∼10 pA level at 3.0 V drain–source bias. Moreover, the unique band alignment facilitates the photo-electrons flow and blocked photo-holes in the BP channel. The photoresponsivity can reach 1.43 A/W at near infrared light with λ = 1342 nm. Our work suggests an effective scheme to design high performance electronic and optoelectronic devices assembled by 2D materials.