Bound for only ten quadrillionths of a second
Graphene is celebrated as an extraordinary material. It consists of pure carbon, only a single atomic layer thick. Nevertheless, it is extremely stable, strong, and even conductive. For electronics, however, graphene still has crucial disadvantages. It cannot be used as a semiconductor, since it has no bandgap. By sticking hydrogen atoms to graphene such a bandgap can be formed. Now researchers from Göttingen and Pasadena (USA) have produced an “atomic scale movie” showing how hydrogen atoms chemically bind to graphene in one of the fastest reactions ever studied.
The international research team bombarded graphene with hydrogen atoms. “The hydrogen atom behaved quite differently than we expected,” says Alec Wodtke, head of the Department of Dynamics at Surfaces at the Max Planck Institute (MPI) for Biophysical Chemistry and professor at the Institute of Physical Chemistry at the University of Göttingen. “Instead of immediately flying away, the hydrogen atoms ‘stick’ briefly to the carbon atoms and then bounce off the surface. They form a transient chemical bond,” Wodtke reports. And something else surprised the scientists: The hydrogen atoms have a lot of energy before they hit the graphene, but not much left when they fly away. Hydrogen atoms lose most of their energy on collision, but where does it go?