Transistors in today’s electronic devices require semiconductors, but high performance electronics of the future will require new transistor materials. One possible candidate is graphene, a conductive material that can become a semiconductor in the form of nanoribbons.
Producing transistors based on graphene nanostructures is nevertheless a major challenge.
“The smallest details in the atomic structure of these graphene bands have massive effects on the size of the energy gap and thus on how well-suited nanoribbons are as components of transistors,” according to the Federal Laboratories for Materials Science and Technology (Empa). “On the one hand, the gap depends on the width of the graphene ribbons, while on the other hand it depends on the structure of the edges.”
Empa researchers in collaboration with the Max Planck Institute for Polymer Research and the University of California at Berkeley have now succeeded in growing ribbons exactly nine atoms wide with a regular armchair edge from precursor molecules. These structures now have a relatively large and – more importantly – a precisely defined energy gap.
After a few unsuccessful first attempts, the researchers made some important findings that allowed them to integrate the graphene ribbons into nanotransistors.
“In the future, the ribbons should no longer be located criss-cross on the transistor substrate, but rather aligned exactly along the transistor channel. This would significantly reduce the currently high level of non-functioning nanotransistors,” Empa explains.