Figure 2

(Left panel) SHIM images of graphene-based pads with longer connecting strips that have been fabricated using direct-write He⁺ lithography.

Areas (i) and (ii) are isolated graphene regions within the device. (Top left) Nonconducting graphene pad due to insufficient supply of electrons through the thin conducting graphene strip (~12 nm). (Middle left) Onset of slight conduction in graphene pad as the width of the conducting strip is increased to 18 nm. Thermal noise is also evident in the pad. (Bottom left) Fully conducting graphene pad with conducting strip width of 20 nm. (Right panel) SEM images of the exact same structures indicating that insufficient electrons in the graphene pads (top and middle) are compensated by the electron beam. Scale bar is 50 nm.