The potential for carbon to displace silicon as the preferred material for integrated circuits appears brighter with the development of metallic graphene nanoribbons. These structures can function as wires in carbon-based transistors and circuits that boost the energy efficiency of computers and other electronic devices.

Researchers from the University of California Berkeley, Columbia University, U.S. Lawrence Berkeley National Scanning tunneling microscope image of wide-band metallic graphene nanoribbon. The structure’s backbone has a width of 1.6 nm. Source: Daniel Rizzo/University of California BerkeleyLaboratory and the University of Washington applied a bottom-up fabrication technique to produce the nanoribbons. By connecting short segments of nanoribbon, electrons in each segment can be arranged to form a desired topological state with tunable semiconducting properties. This approach yielded a conducting metal wire tens of nanometers long and 1.6 nm wide. The electronic state of the newly formed structure was that of a metal, with each segment contributing a single conducting electron.

The metallicity of the graphene nanoribbons, which may prove useful in studying exotic quantum phases in a single dimension, was demonstrated using scanning tunneling spectroscopy. Carbon-based computers engineered with this material could potentially switch many times faster than silicon computers and use only fractions of the power.