© Fig. 1b des Nature Comm. Papers
© Fig. 1b des Nature Comm. Papers

Research shows graphene can carry high electric currents

New experiments have shown that it is possible for extremely high currents to pass through graphene, allowing imbalances in electric charge to be rapidly rectified.

An international research team led by Professor Fritz Aumayr from the Institute of Applied Physics at TU Wien, Austria, was able to demonstrate that the electrons in graphene are extremely mobile and react very quickly.

Impacting xenon ions with a particularly high electric charge on a graphene film caused a number of electrons to be torn away from the graphene in a particular spot. However, the material was able to replace the electrons within some femtoseconds (one quadrillionth of a second). This resulted in extremely high currents, which would not be maintained under normal circumstances.

The Helmholtz-Center Dresden-Rossendorf and the University of Duisburg-Essen, Germany, participated in the experiment alongside TU Wien.

Elisabeth Gruber, a PhD student from Aumayr’s research team, said: “We work with extremely highly charged xenon ions.

“Up to 35 electrons are removed from the xenon atoms, meaning the atoms have a high positive electric charge.”

These ions are then fired at a free-standing single layer of graphene, which is clamped between microscopically small brackets.

Gruber added: “The xenon ion penetrates the graphene film, thereby knocking a carbon atom out of the graphene – but that has very little effect, as the gap that has opened up in the graphene is then refilled with another carbon atom.

“For us, what is much more interesting is how the electrical field of the highly charged ion affects the electrons in the graphene film.”

This high electron mobility in graphene is of great significance for a number of potential applications.

Aumayr said: “The hope is that for this very reason, it will be possible to use graphene to build ultra-fast electronics. Graphene also appears to be excellently suited for use in optics, for example in connecting optical and electronic components.”