* Internet connection speeds could be tens of times faster
* Combining graphene with metallic nanostructures boosts
* Super-thin material has potential for photonics,
LONDON, Aug 30 British scientists have devised a
way of using graphene, the thinnest material in the world, to
capture and convert more light than previously, paving the way
for advances in high-speed Internet and other optical
In a study in the journal Nature Communication, the team --
which included last year's Nobel Prize-winning scientists Andre
Geim and Kostya Novoselov -- found that by combining graphene
with metallic nanostructures, there was a 20-fold enhancement in
the amount of light the graphene could harvest and convert into
Graphene is a form of carbon just one atom thick and yet 100
times stronger than steel.
"Many leading electronics companies consider graphene for
the next generation of devices. This work certainly boosts
graphene's chances even further," said Novoselov, a Russian-born
scientist who with Geim won the 2010 Nobel Prize for physics for
research work on graphene.
Previous research has shown that electrical power can be
generated by putting two closely-spaced metallic wires on top of
graphene and shining light on the whole structure, effectively
making a simple solar cell.
The researchers explained that due to the particularly high
mobility and velocity of the electrons in graphene, such
graphene cell devices can be incredibly fast -- tens or
potentially hundreds of times faster than communication rates in
the fastest Internet cables currently in use.
The main stumbling block to practical applications has so
far been the cell devices' low efficiency, the researchers said.
The problem is that graphene absorbs little light -- only around
3 percent -- with the rest going through without contributing to
the electrical power.
In a collaboration between the Universities of Manchester
and Cambridge, Novoselov's team found they could solve this
problem by combining graphene with tiny metallic structures
known as plasmonic nanostructures, which are specially arranged
on top of graphene.
By using the plasmonic enhancement, the light-harvesting
performance of graphene was boosted by 20 times without
sacrificing any of its speed, they wrote in their study. Future
efficiency could be improved even more, they said.
"We expected that plasmonic nanostructures could improve the
efficiency of graphene-based devices but it has come as a
pleasant surprise that the improvements can be so dramatic,"
said Alexander Grigorenko, an expert in plasmonics and a leading
member of the team. "Graphene seems a natural companion for
Andrea Ferrari of Cambridge University's engineering
department, who also worked on the team, said the findings show
graphene's great potential in photonics and in developing
electronic devices that channel and control light. He said the
combination of its special optical and electronic properties
with plasmonic nanostructures could be fully exploited.
(Reporting by Kate Kelland; Editing by Roger Atwood)