Graphene was discovered in 2004 by University of Manchester scientists, led by Andre Geim and Kostya Novoselov, and the “wonder material” is one of the hottest topics in physics and materials science today thanks to its great potential for making future electronic devices. Graphene is an excellent conductor of electricity because, as well as being extremely thin and a semiconductor, electrons move through the material at extremely high speeds. This is because they behave like relativistic particles that have no rest mass. This, and other unusual physical properties, means that graphene is often touted to replace silicon as the electronic material of choice and might be used to make faster transistors than any that exist today.
Now, the Manchester team has converted graphene into graphane by exposing it to atomic hydrogen. One hydrogen atom is added per carbon atom without altering or damaging the crystallographic structure of graphene itself, say the researchers. But graphane has remarkably different properties to graphene because it is an insulator.
Fine tuning graphene's properties
“This is the first step in being able to fine tune the electronic properties of graphene by attaching various species to its scaffolding,” Novoselov told nanotechweb.org. “It is a new look at graphene, if you like, with far reaching and promising consequences.”
The next step would be to learn how to fine tune the electronic properties by adding other chemicals, with perhaps different arrangements of these species on graphene’s surface, says Novoselov.
“The modern semiconductor industry makes use of the whole periodic table, from insulators to semiconductors to metals. But what if a single material could be modified so that it covers the entire spectrum needed for electronic applications?” added Geim. “Imagine a graphene wafer with all interconnects made from highly conductive, pristine graphene whereas other parts are modified chemically to become semiconductors - and work as transistors - or become insulators.”
And that’s not all: the reaction is reversible because graphane can be converted back into graphene by heating it up so that the hydrogen is removed.
Graphane might also find use in hydrogen-fuel technologies because it has a very high hydrogen density.
The researchers published their work in Science.