Fig. 4: Photoelectric characterization of the infrared response under visible light switching modulation (5 nm thick C₆₀ device).

a Time-dependent photoresponse of the intrinsic infrared 1310 nm (20 mWcm⁻²) positive response and 1310 nm response under 650 nm 20 mWcm⁻² light modulation measured by an oscilloscope. b Analysis of the response time of graphene/C₆₀/pentacene devices at different signal (808 nm) and modulation (650 nm) light power densities, V_ds = 1 V. c Schematic diagram of infrared light (808–1550 nm) working as signal light under the visible-light-modulation-induced carrier transfer process; the small red arrow represents signal light-induced charge transfer. d Summary of the enhancement in the device performance of the bilayer/graphene heterojunction phototransistor in terms of the photoresponse and response time by light modulation (left panel modulation: signal light power density: 28.3 μWcm⁻² (405 nm), 17.4 μWcm⁻² (450 nm), 36.7 μWcm⁻² (520 nm) 23.4 μWcm⁻² (650 nm), and modulation light power density of nearly 300 μWcm⁻²; right panel modulation: signal and modulation light power densities of ~20 mWcm⁻²)