Keeping electronics cool in high power applications such as telecommunications and building electronics on the nanoscale are two areas where there is an alternative to traditional silicon—electronics using diamond.

To study the potential of diamond-based electronics, Dr Chris Pakes and his team at the Atom-scale Research Laboratory at La Trobe University have been inducing electrical conductivity—allowing an electrical current to flow—on the surface of synthetic diamonds.

The researchers do this by seeding the diamond surface with molecules called fullerenes. The group has recently shown that by introducing porphyrin, a molecule that interacts with fullerene, the level of conductivity in the diamond can be controlled.

In contrast to silicon-based circuits, diamond can withstand temperatures of a few hundred degrees without cooling and are much more durable.

“The electrical conductivity is confined to a very thin sheet just below the surface, so the diamond can be used to build nanoscale devices for miniature chemical and biological sensors and devices for microwave electronics, like that in mobile phones,” Chris says. “The interaction between different molecules on the surface can now be used to control the properties of these devices.”

The next step for the group, which works closely with the Australian Synchrotron in Melbourne, is to find a way to control the conductivity of the diamond remotely—being able to switch currents on and off using a magnetic or light signal.

One of the key collaborators in the project is Prof Lothar Ley, a leading figure in the field in diamond science, who has recently taken up a distinguished professorship at La Trobe University.

Photo: Introducing the porphyrin molecule onto the surface of the diamond can control the level of conductivity.
Credit: Atom-Scale Research Laboratory

Atom-Scale Research Laboratory, La Trobe University, Chris Pakes, C.Pakes@latrobe.edu.au