(a) Schematic of the photodetector and AFM characterization of SWNT–graphene hybrid film (middle: scale bar, 200 nm; right: scale bar, 20 nm). (b) The I_SD–V_G transfer curve of device with increasing 650 nm illumination powers. V_SD=0.5 V. Inset: the optical image of the SWNT–graphene device (scale bar, 10 μ m ). (c) Temporal response of the SWNT–graphene hybrid photodetector under 650 nm illumination. (d) The dependence of responsivities of photodetector on the optical power at different illumination wavelengths from visible to near-infrared range (405, 532, 650, 980, and 1550 nm). (e) Photocurrent spectral response can be tuned by varying the gate voltage. V_D=−10 V. Panels (a)–(d) are reproduced from Ref. [50] with permission from the Nature Publishing Group. Panel (e) is reproduced from Ref. [60] with permission from the National Academy of Sciences.