Visible-to-near-infrared photodetector based on graphene–MoTe2–graphere heterostructure**Project supported by the National Natural Science Foundation of China (Grant No. 21405109) and the Seed Foundation of State Key Laboratory of Precision Measurement Technology and Instruments, China (Pilt No. 1710).

Abstract

Graphene and transition metal dichalcogenides (TMDs), two-dimensional materials, have been investigated wildely in recent years. As a member of the TMD family, MoTe2 possesses a suitable bandgap of ∼ 1.0 eV for near infrared (NIR) photodetection. Here we stack the MoTe2 flake with two graphene flakes of high carrier mobility to form a graphene–MoTe2–graphene heterostructure. It exhibits high photo-response to a broad spectrum range from 500 nm to 1300 nm. The photoresponsivity is calculated to be 1.6 A/W for the 750-nm light under 2 V/0 V drain–source/gate bias, and 154 mA/W for the 1100-nm light under 0.5 V/60 V drain–source/gate bias. Besides, the polarity of the photocurrent under zero Vds can be efficiently tuned by the back gate voltage to satisfy different applications. Finally, we fabricate a vertical graphene–MoTe2–graphene heterostructure which shows improved photoresponsivity of 3.3 A/W to visible light.