2D MoS2/CuPc heterojunction based highly sensitive photodetectors through ultrafast charge transfer

Abstract

Photodetectors (PD) with high detectivity, high quantum efficiency and fast response are fundamental units to achieve sensors, imagers, and many others functional optoelectronics. Here we demonstrate high performance vertical stacked 2D MoS2/CuPc heterojunction based photodetectors with high sensitivity, high external quantum efficiency and ultrafast response time. The functional p-type organic thin film of CuPc was thermally evaporated on n-type two-dimension (2D) MoS2 monolayer to create an ideal type II heterojunction interface, where ultrafast charge transfer (CT) occur in 16 ps, followed by effective exciton separation and charge collection. As a result, photoresponse time as fast as 436 μs has been obtained for 2D MoS2/CuPc PDs, as well as a profound responsivity of 3.0×103A/W and a detectivity of 2.0 × 1010 Jones with a peak external quantum efficiency (EQE) of 483%. This work suggests a feasible route to develop ultrasensitive visible light photodetector by 2D materials.