Field emission from single and few-layer graphene flakes

We report the observation and characterization of field emissioncurrent from individual single- and few-layer graphene flakes laid on a flat SiO2/Si substrate. Measurements were performed in a scanning electron microscope chamber equipped with nanoprobes which allowed local measurement of the field emissioncurrent. We achieved field emissioncurrents up to 1 ?A from the flat part of graphene flakes at applied fields of few hundred volt per micrometer. We found that the emission process is stable over a period of several hours and that it is well described by a Fowler-Nordheim model for currents over five orders of magnitude.