Figure 7
(a–e) Experiments: Plots of contact resistance vs. graphene sheet resistance for five different graphene-metal contacts (nickel/gold (a), palladium (b), copper (c), platinum-gold (d), gold (e)). Each point corresponds to a different back-gate voltage V bg (−40 V, −39 V, −37 V, −33 V, −30 V, −28 V, −25 V, −20 V). In all cases the correlation coefficient of the linear fit is very high (R > 0.96), confirming our interpretation. (f) Illustration of the simple model of graphene-metal contact and (g) condition of minimum contact resistance, obtained by properly adjusting the graphene Dirac point near the contacts.
