Ultrasensitive Near-Infrared Photodetectors Based on a Graphene–MoTe2–Graphene Vertical van der Waals Heterostructure

Graphene and other layered materials, such as transition metal dichalcogenides, have rapidly established themselves as exceptional building blocks for optoelectronic applications because of their unique properties and atomically thin nature. The ability to stack them into van der Waals (vdWs) heterostructures with new functionality has opened a new platform for fundamental research and device applications. Nevertheless, near-infrared (NIR) photodetectors based on layered semiconductors are rarely realized. In this work, we fabricate a graphene–MoTe2–graphene vertical vdWs heterostructure on a SiO2/p+-Si substrate by a facile and reliable site-controllable transfer method and apply it for photodetection from the visible to NIR wavelength range. Compared to the layered semiconductor photodetectors reported thus far, the graphene–MoTe2–graphene photodetector has a superior performance, including high photoresponsivity (∼110 mA W–1 at 1064 nm and 205 mA W–1 at 473 nm), high external quantum efficiency (EQE; ∼...