▎ 摘　　要

We report the observation and characterization of field emission current from individual single- and few-layer graphene flakes laid on a flat SiO(2)/Si substrate. Measurements were performed in a scanning electron microscope chamber equipped with nanoprobes which allowed local measurement of the field emission current. We achieved field emission currents up to 1 mu 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. (C) 2011 American Institute of Physics. [doi:10.1063/1.3579533]