Given the edge

Researchers at the University of Illinois at Urbana-Champaign have shown in experiments that the molecular structure of graphene’s edges significantly influences the material’s electronic properties.

Graphene, which was first isolated and studied in Europe, is a single-atom-thick sheet of carbon that is said to have a great deal of potential in future nanoelectronics applications.

Graphene consists of a hexagonal lattice of carbon atoms. While scientists have predicted that the orientation of atoms along the edges of the lattice would affect the material's electronic properties, the prediction had not been proven experimentally.

‘Our experimental results show, without a doubt, that the crystallographic orientation of the graphene edges significantly influences the electronic properties,’ said Joseph Lyding, a professor of electrical and computer engineering. ‘To utilise nanometre-size pieces of graphene in future nanoelectronics, atomically precise control of the geometry of these structures will be required.’

To carry out their work, the researchers developed a method for cutting and depositing nanometre-size pieces of graphene on atomically clean semiconductor surfaces such as silicon. Then they used a scanning tunnelling microscope to probe the electronic structure of the graphene.