Figure 2
(a) Raster images obtained at different gate voltages showing the transmitted THz power as well as average, real sheet conductance value from 0.5–0.9 THz. Scale bars are 5 mm. See Supplementary information for overlays with the optical image in Fig. 1(b) (b) Graphene sheet conductance spectra from the central region at series of different gate voltages. Full lines: real part. Dashed lines: imaginary part. Uncertainty on Re[σs] and Im[σs] due to substrate thickness variations of 200 nm shown as shaded confidence bands (c) Average, real, gate-induced sheet conductance from 0.5 to 0.9 THz as a function of Vg for 3 distinct positions of the mapped area. Circles, triangles and squares are experimental data and the full lines are linear fits to the data for 0 V < Vg < 18 V and 26 V < Vg < 40 V for hole and electron mobilities, respectively. (d)+(e) maps showing the spatial distribution of hole field effect mobility, μFE, and carrier density, ns, at Vg = 0 V across the CVD graphene film evaluated at 0.5–0.9 THz.
