First functional transistor for graphene a fact
Graphene has been under the spotlight for many years as a material for making ultrafast computer chips. The theory was rock solid but had yet to be realised in practice. At last this has been achieved. On Friday scientists published an article about the first working graphene transistor in the journal Science. One of the researchers involved is FOM workgroup leader Prof. Mikhail Katsnelson.
The problem with a transistor made of graphene was that the current passed through the material too easily and that is not meant to happen. Transistors, the miniscule switches inside a computer chip, must be able to allow the current to pass through but also to hold it back if necessary.
Modulating the conductance of graphene
Katsnelson and his team have now accommodated graphene's tendency to conduct too well by combining it with thin insulating layers of a different material. These layers combined with layers of graphene have exactly the right semiconducting characteristics. "Years ago we had already experimented with working graphene transistors but it is the shape of this switch that makes it so special," Katsnelson adds over the phone. "Unlike the earlier models, this is particularly suitable for functioning inside a computer chip."
Faster computer chips
This technology is still in its infancy but it is expected that the graphene transistors will ultimately be much smaller than the current generation of transistors (which are made of silicon). The smaller the transistor the better: it means that more can be fitted onto a chip as a result of which its computational power increases. Katsnelson is very pleased with this discovery. "This is a real technological breakthrough, which we have awaited for years," he says.
Nobel Prize research
Besides Katsnelson the science publication also contains a contribution from the Nobel Prize winners Prof. Andre Geim and Prof. Kostya Novoselov (former FOM PhD student). They won the Nobel Prize for Physics in 2010 for their research into graphene. Shortly after that, Geim was the main speaker Physics@FOM Veldhoven 2011.