Although transistors developed by using carbon nanostructures seem to be a distant dream, they could become reality in the very near future. An international team of scientists in collaboration with Empa has been successful in developing nanotransistors by using graphene ribbons with a width of just few atoms. The study has been published in the latest issue of the Nature Communications journal.
Graphene ribbons with a width of just few atoms, or graphene nanoribbons, possess unique electrical characteristics that render them promising for application to nanoelectronics in the future: although graphene, which is a honeycomb-shaped carbon layer with a width of just one atom, is conductive, it can transform into a semiconductor when in the form of nanoribbons. This indicates that graphene includes an adequately large band or energy gap where no electron states can exist—it can be turned on and off and hence can be used as a major component in nanotransistors.
However, even the minute features in the atomic structure of the graphene bands have enormous impacts on the width of the band gap and consequently on the suitability of nanoribbons as transistor components. While the band gap is based on how wide the graphene ribbons are, it is also based on the structure of the edges. As graphene comprises equilateral carbon hexagons, the border might be a zigzag or ‘armchair’ shape, dependent on the alignment of the ribbons. Although bands that have a zigzag edge act as metals, or conductive, the ones that have the armchair edge behave like semiconductors.
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Source: AZO NANO