Figure 6.

(a) Measurement of the gate voltage-dependent drain-source current of a graphene strip on Si/SiO₂. The strip was 500 nm wide and 3.9 μm long. The current reached a minimum at V_GS = V_D = 50 V. A source-drain voltage of V_DS = 10 mV was used for the measurements; (b) Mean-free-path lengths deduced from the graphene sample in Figure 6a. At zero gate voltage, the charge carriers had λ_MFP = 70 nm; (c) Simulated current-voltage compared with measured current-voltage characteristics of a geometric diode with a 50 nm neck width. The charge carriers were assumed to have λ_MFP = 70 nm.