Figure 1. Photocurrent generation in vertical heterostructures of graphene–MoS₂–graphene.

a, Schematic illustration of the three-dimensional device layout. b, Schematic illustration of the side view of the device, with the semiconducting multilayer MoS₂ sandwiched between the Gr_T and Gr_B electrodes. Red and blue colours indicate electrons and holes, respectively. The silicon substrate can be used as a back-gate electrode with 300 nm SiO₂ as the dielectric layer. c, Experimental current–voltage characteristic of the vertical device in the dark (blue) and under illumination (red) by a focused laser beam (wavelength, 514 nm; power, 80 µW; spot size, 1 µm).