Figure 2

Hot electrons generated by Joule heating in disordered graphene bolometer.

(a) A schematic for heat dissipation in a device. The graphene lattice and the electrodes are assumed at the bath temperature T₀¹³. Two heat dissipation paths, diffusion and e-p scattering are denoted by and , respectively. The longitudinal temperature distribution T_e(x) is drawn in solid line, when . The temperature is relatively uniform, while it deviates above the electrodes due to diffusion. (b) Strong nonlinear resistances as a function of the bias current I_dc. Black, red, blue lines are data at B = 0, 1, 5 T, respectively. The magnetoresistance is shown in the inset. The solid circles denote the fields in which the bias dependence were measured. To minimize heating by the a.c. current, 0.5 nA a.c. current was used at low bias, while 10 nA was applied at bias I_dc > 500 nA to enhance the signal-to-noise ratio. (c) Scaling of the bias dependence of R in (b). T_e is obtained from R according to R – T, while P = I × V. The inset is a zoom-in view of the area enclosed by the dashed line in the main panel, which shows that the scaling is very good at low bias, too.