Fig. 3
From: Towards sensitive terahertz detection via thermoelectric manipulation using graphene transistors
The photoconductive response under 0.12 THz radiation (power density of 0.6 mW/cm2) for wide- and narrow-channel devices. a Schematic of the wide-channel device (W ~ 60 μm). b Bias voltage UAD dependence of the photocurrent Iph-AD. c Temporal response of the wide-channel device under fast on/off THz radiation modulation. d Schematic of the narrow-channel device (W ~ 6 μm), where s denotes the slit width between the two paired contacts. e Bias voltage UAD dependence of photocurrent Iph-AD in devices with different slits. f Response/recovery times for the narrow-channel device following modulated THz radiation. g Cross-section schematic of the electrical configuration for photoconductive measurement. The spaces between the contacts are shown in different colors representing the E-field distribution for the case in which the paired fingers are dislocated from the center. h Zero-bias photocurrent response due to hot-carrier diffusion from the hot to the cool side when UAD < ΔUph-AD. i Photoconductive photocurrent response under finite bias voltage UAD > ΔUph-AD; the generated hot carriers are efficiently extracted under finite bias with a photoconductive gain. ΔUph-AD = Iph-AD·RAD is the open-circuit voltage
