Fig. 1: Characterization, electrical and optical properties of multilayered InSe device.

a Schematic sketch of the back-gate InSe-based device. b Optical image of the multilayered InSe device. Scale bar: 10 μm. c Height profile of the layered InSe channel. d Raman spectrum of the InSe flake with an excitation wavelength of 532 nm. e Output characteristics of the InSe device tested in the dark at various Vbg. f Transfer characteristics at different illumination intensities of a 405-nm laser at Vds = 0.5 V. g The extracted α value as a function of Vbg. h Responsivity (R) of the InSe device as a function of the laser power density under diverse Vbg with Vds = 0.5 V.