Material development on the nanoscale
Graphene is a semiconductor when prepared as an ultra-narrow
ribbon – although the material is actually a conductive material. Researchers
from Empa and the Max Planck Institute for Polymer Research have now developed
a new method to selectively dope graphene molecules with nitrogen atoms. By
seamlessly stringing together doped and undoped graphene pieces, they were able
to form ”heterojunctions” in the nanoribbons, thereby fulfilling a basic
requirement for electronic current to flow in only one direction when voltage
is applied – the first step towards a graphene transistor. Furthermore, the
team has successfully managed to remove graphene nanoribbons from the gold substrate
on which they were grown and to transfer them onto a non-conductive material.