Astonishing conductivity helped the discoverers of graphene win the Nobel prize in physics in 2010. Now a way to switch off the easy flow of electrons in this wonder form of carbon is bringing superfast graphene computers closer.
A sheet-like molecule just one carbon atom thick, graphene offers much less resistance to the flow of electrons than silicon. It has been hailed for its potential as the basis for computer circuits that operate at unprecedented speed. "It's an extremely promising material," says Konstantin Novoselov, who shared the Nobel prize with his co-discoverer, Andre Geim, both at the University of Manchester, UK.
But the ease of electron flow also creates a problem. To perform calculations, computers need to turn the flow of electricity on and off in their circuits. The gates that open and close to regulate the flow are called transistors. Making graphene-based transistors has proven difficult because it is such a good conductor.
Previous attempts have involved electrons confined to a single layer of graphene, but these still suffer from a leakage of electrons when the transistor is in its "off" state.
Now Novoselov and colleagues have found a way to overcome this leakage problem by sandwiching a layer of molybdenum disulfide between two layers of graphene. The molybdenum acts as an insulator, preventing electrons from flowing in the normal way from one graphene layer to the other. This constitutes an "off" state.
To read more, click here.