21 August 2019
Atomic-scale devices are now a possibility
Published online 16 May 2016
New technique allows scientists to manipulate re-arrangement of atoms in nanostructures.
With the ultimate goal of designing atomic-scale electronic devices, a group of scientists have been using electrical currents to displace atoms in carbon nanotubes and graphene1.
Long exposure to an intense current can rearrange atoms, but until this experiment, it was not clear how this works for carbon nanotubes and graphene.
Using a computer code and first principle simulations, physicists from King Abdullah University of Science and Technology (KAUST), Saudi Arabia, and Trinity College, Ireland, investigated current-induced directional motion of adsorbed carbon atoms (adatoms) on the surfaces of carbon nanotubes and graphene.
In carbon-based systems, the adatoms can potentially move when a pulsed current is applied. The current reduces the energy barrier that an atom has to overcome when moving between two positions.
Such reduction is directional — the barrier increases when an adatom moves against the current flow, but it decreases when the adatom moves in the opposite direction along the current flow. The adatoms also gain significant energy as they migrate along the current-driven path, the researchers say.
“In the future, this technique will allow us to manipulate difficult chemical reactions, dope semiconductors and create high-performance transistors,” says principal investigator Udo Schwingenschlögl.
- Obodo, J. T., et al. U. Current-induced changes of migration energy barriers in graphene and carbon nanotubes. Nanoscale http://dx.doi.org/10.1039/C6NR00534A (2016).