US engineers have developed a technique that replaces silicon with carbon to make next-generation semiconductors.

Boffins at Princeton University said that the electronics industry has pushed the capabilities of silicon - the material at the heart of all computer chips - to its limit, and that carbon could offer a viable replacement.

Stephen Chou, professor of electrical engineering at Princeton, explained that graphene, a single layer of carbon atoms arranged in a honeycomb lattice, could allow electronics to process information and produce radio transmissions 10 times more efficiently than silicon-based devices.

Until now, however, switching from silicon to carbon has not been possible because technologists believed they needed graphene material in the same form as the silicon used to make chips, i.e. a single crystal of material 8in or 12in wide.

The largest single-crystal graphene sheets made to date have been no wider than two millimetres, not big enough for a single chip.

Professor Chou and researchers in his lab realised that a big graphene wafer is not necessary, as long they could place small crystals of graphene only in the active areas of the chip.

They developed a method to achieve this and demonstrated it by making high-performance working graphene transistors.

"Our approach is to completely abandon the classical methods that industry has been using for silicon integrated circuits," said Professor Chou.