Jul 7, 2011 Reduced graphene oxide makes good field emitter
Researchers in the US, Japan and the UK have observed extremely
low-threshold field electron emission from atomically thin edges
of reduced graphene oxide. The interference pattern of the
emitted electrons also suggests that the emitted electron beams
are coherent, a result that could be important for making new
electron sources for e-beam lithography, X-ray tubes, microwave
amplifiers and even rocket thrusters. Most electron emitters
such as X-ray sources use thermal excitations – or thermionic
emission – to generate high-current electron beams. However,
such sources are far from ideal because they are unstable and
bulky, and heat up their surroundings. Cold cathode emitters
that remain at room temperature and provide high emission
current density at low electric fields are thought of as being
much better alternatives. Carbon nanotubes and other carbon-
based materials are promising in this respect because they are
bright field emitters and the elect