Atomic force microscope nanolithography of graphene: Cuts, pseudocuts, and tip current measurements

We investigate atomic force microscope nanolithography of single and bilayer graphene. In situ tip current measurements show that cutting of graphene is not current driven. Using a combination of transport measurements and scanning electron microscopy we show that while indentations accompanied by tip current appear in the graphene lattice for a range of tip voltages, real cuts are characterized by a strong reduction in the tip current above a threshold voltage. The reliability and flexibility of the technique is demonstrated by the fabrication, measurement, modification, and remeasurement of graphene nanodevices with resolution down to 15 nm. (C) 2011 American Institute of Physics. [doi:10.1063/1.3573802]