Thursday, July 09, 2009


An international team of physicists has discovered that electrons move much more easily through graphene than any other known material. Their findings strengthen the belief of some researchers that graphene — which is a 2D sheet of carbon just one atom thick and a semiconductor — might be the best material for making electronic devices of the future.

Now, Andre Geim of Manchester University and colleagues in Russia, the Netherlands and the US have found that the intrinsic mobility of graphene was around 200,000 cm2/Vs. Graphene, which is a 2D sheet of carbon just one atom thick, is ultimately thin but has a higher electronic quality than any known material. Graphene is normally not perfectly flat but instead has a corrugated appearance and these corrugations vibrate as the graphene warms up.

However, two big challenges still need to be overcome before applications like graphene logic circuits see the light of day. The high mobility value also means that graphene could be used to make devices that operate in the the terahertz region of the electromagnetic spectrum — something that is very difficult today. The researchers say that the intrinsic mobility could go even higher if the impurities in graphene were cleaned up — and if the corrugations could be removed.

Geim said that although he knew that electrons in graphene could move long distances (longer than in conventional semiconductors), he did not expect that the material could outperform carbon nanotubes in this respect — or indeed the current record holder indium antimonide.Its high intrinsic mobility (or electronic quality as it also known) means that graphene is the only material where electrons at room temperature can move thousands of interatomic distances without scattering.