US and French researchers are exploring thin layers of graphite, graphene, as a semiconductor.
Consisting of less than 10 layers of graphite, and with a similar chicken wire structure to an unrolled carbon nanotube, the teams hope to use the material for electronic systems that manipulate electrons as waves rather than particles.
“We expect to make devices of a kind that don’t really have an analogue in silicon-based electronics, so this is an entirely different way of looking at electronics,” said Professor Walt de Heer from Georgia Tech’s school of physics.
“Our ultimate goal is integrated electronic structures that work on diffraction of electrons rather than diffusion of electrons. This will allow the production of very small devices with very high efficiencies and low power consumption.”
Graphene can be patterned by traditional lithography and, following a decade in nanotube research, de Heer sees graphene as a better bet for mass production than nanotubes.
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Professor Walt de Heer
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“Using narrow ribbons of graphene, we can get all the properties of nanotubes because those properties are due to the graphene and the confinement of the electrons, not the nanotube structures,” he said.
The key to properties of graphene circuitry is the width of the ribbons, which confine the electrons in a quantum effect similar to that seen in carbon nanotubes. The width of the ribbon controls the material’s band-gap.
Feature sizes down to 80nm have been created and the teams are working towards 10nm.
The material is produced by baking silicon carbide wafers to drive the silicon off, and Georgia claims 25,000cm2/Vs mobility, compared with 1,500 for doped silicon.
The research is being undertaken at Georgia Tech and the Centre National de la Recherche Scientifique (CNRS) in France.
www.cnrs.fr
www.gatech.edu