Chemical route towards graphene electronic devices

1 min read

Electronic components, such as diodes and tunnel barriers, can be incorporated into single graphene wires – or nanoribbons – with atomic precision say researchers from Aalto University in Finland and Utrecht University in the Netherlands.

Graphene itself does not have the characteristics needed to switch electrical currents on and off and smart solutions must be found for this particular problem.

"We can make graphene structures with atomic precision. By selecting certain precursor substances, we can code the structure of the electrical circuit with extreme accuracy," explains Professor Peter Liljeroth from Aalto University.

According to the team, the electronic properties of graphene can be controlled by synthesising it into nanoribbons. Previous research has shown that the ribbon's electronic characteristics are dependent on its atomic width: a ribbon five atoms wide behaves similarly to a metallic wire with good conduction characteristics, but adding two atoms turns the ribbon into a semiconductor.

"We can now seamlessly integrate five atom-wide ribbons with seven atom-wide ribbons. That gives you a metal-semiconductor junction, which is a basic building block of electronic components," says assistant professor Ingmar Swart from Utrecht University.

To produce the electronic graphene structures, the researchers evaporated the precursor molecules onto a gold crystal, which yielded new chemical compounds.

"This is a different method from that currently used to produce electrical nanostructures, such as those on computer chips. For graphene, it is so important that the structure is precise at the atomic level and it is likely that the chemical route is the only effective method," Swart concludes.