Shrinking circuitry with graphene: Carbon
- Available online 24 March 2012.
Fundamentally, graphene is merely an isolated layer of graphite. Yet, this simplistic description belies a range of unique properties such as strength, flexibility and novel optoelectronic behavior. One area in which thin coatings of graphene might be used are in lightweight, flexible, and paper-thin devices, and as molecular scale components for a future generation of micro, or even nano, electronics devices.
Graphene's properties hold promise for applications in optoelectronics and engineering, but it is atomic-level defects in the carbon material that could pave the way forward to smaller and faster electronic devices.
Researchers at Oak Ridge National Laboratory, in Tennessee, USA, suggest that replacing the occasional carbon atom in graphene with a silicon atom to form a point defect could allow the material to couple light with electrons via a localized plasmon enhancement process [Zhou et al., Nature Nanotech (2012) doi:10.1038/nnano.2011.252].
“In this proof of concept experiment, we have shown that a tiny wire made up of a pair of single silicon atoms in graphene can be used to convert light into an electronic signal, transmit the signal and then convert the signal back into light,” explains ORNL's Juan-Carlos Idrobo. He and his colleagues observed the phenomenon using aberration-corrected scanning transmission electron microscopy. The technique was able to provide an image of the plasmon response, the optical-like signals, due to the silicon point defects. The team explains that the silicon atoms appear to behave as atomic-scale antennae in the petahertz frequency range to boost the signals in their prototype plasmonic device.
Plasmon map showing that the substitutional Si atom acts as an atomic antenna
