Fig. 4
From: Towards sensitive terahertz detection via thermoelectric manipulation using graphene transistors
The direct photocurrent/photovoltaic response Iph-AD under 0.12 THz radiation (power density of 0.6 mW/cm2), tuned by the bias voltage UAB between contacts A and B. a Schematic of the bias-field configuration. The photocurrent Iph-AD is readout as a function of the bias voltage UAB. b UAB dependence of the dark current IAD; the bias voltage UAD is approximately 100 mV. c Derivation of conductance σAD vs. UAB: σAD−1dσAD /dUAB. d Direct photocurrent Iph-AD vs. UAB under 0.12 THz radiation. The inset shows a similar trend of photocurrent response at 0.3 THz. e Band diagram of the “bias-field effect” induced by direct photocurrent generation. f The symmetry of carrier distribution is broken when the electrical bias UAB is applied due to charge transfer between the metal and graphene33, 34, which ultimately facilitates non-equilibrium hot-carrier diffusion in our devices. T(x) denotes the hot-carrier temperature distribution; S(x) is the Seebeck coefficient
