Graphene at a stretch

Researchers say they have found a simple way to improve the semiconducting properties of the world's thinnest material – simply by stretching it.

The researchers – from Manchester University, the Institute of Materials Science in Madrid, and the University of Nijmegen in the Netherlands – claim that simply stretching graphene – a 2D material just one atom thick – can turn it into a good semiconductor.

Although graphene has become one of the most promising materials for future electronics, one stumbling block has been the lack of an energy 'gap', a common characteristic of silicon and other materials currently used by the semiconductor industry.

While researchers have been able to make graphene-based transistors much smaller and faster than those made from other materials, they have leaked energy even in an idle state making it impossible to use them in integrated circuits.

But Prof Andre Geim, who discovered graphene at Manchester University in 2004,  now says that if forces are applied along three main directions in graphene's honeycomb crystal lattice, a semiconducting gap opens, which is sufficiently large to enable the material to be used in electronic applications.

Geim, director of the Manchester Centre for Mesoscience and Nanotechnology at Manchester University, said: 'Straining graphene can effectively lead to new derivatives that offer better or different properties with respect to the parent material.'

Antonio Castro Neto, physics professor at Boston University and the National University of Singapore, added: 'The influence of strain on the electronic properties is a completely unexplored avenue with a lot of promise.'