Figure 2
Characterization of monolayer graphene.
(a) Schematic of the graphene synthesis process and comparison of the temperature profile vs. time. (b) Representative Raman spectrum of a monolayer graphene film grown on a Cu foil at 1050 °C and then transferred onto a Si (111) substrate. (c) Raman map of the G/2D-bands (left) and the FWHM of the 2D-band (right) of the graphene film transferred onto the Si substrate. The scale bars are all 15 μm. (d) An optical microscopy image of the patterned graphene layer on Si with an Au(35 nm)/Cr(5 nm) bilayer as ohmic contacts for CTLM measurements. (e) The total resistance measured using the CTLM method. The plot shows the total resistance as a function of channel spacing (S = 4–500 μm) after the correction factors were applied. The measured resistances (blue circles) are determined by the CTLM contact structure between the inner and outer contacts with various channel spacing. From the linear fit (red line), the following values are obtained: sheet resistance (Rs), contact resistance (Rc) and transfer length (LT). The error bars represent the standard deviation of the resistance in 5 different devices.
