stephen at melbpc.org.au
stephen at melbpc.org.au
Wed Oct 6 09:30:11 CEST 2010
What's graphene, and why is its development worth a Nobel Prize?
Alan Boyle writes: In just a few years you might be riding in it, tapping
on it as you use your iPhone 9, or watching 3-D TV on a lightweight, big-
screen panel made using graphene.
But wait ... there's more. Sheets of graphene could also be tweaked to
create electronic circuits that are mere molecules thick, or built into a
new generation of body scanners for hospitals or airports.
And it all basically started with a strip of Scotch tape.
The researchers who shared the physics Nobel today, Konstantin Novoselov
and Andre Geim of the University of Manchester, reported back in 2004
that they were able to demonstrate interesting electronic effects with
ultra-thin sheets of carbon that they created "by mechanical
exfoliation ... of small mesas of highly oriented pyrolytic graphite."
In other words, they used Scotch tape to pull thin layers of carbon off a
block of pencil lead.
That was the start of something big. Atom for atom, graphene turned out
to be 100 times stronger than steel, in large part because the single-
layered atoms are tightly bonded together in a honeycomb lattice.
Stronger, lighter composites
One atom-thick sheet is not that tough, but when graphene sheets are
incorporated into composites, you could come up with a material that's
many times stronger than Kevlar.
The Chinese are already working on carbon-nanotube yarn for spacesuits
and bulletproof vests. Graphene composites could be produced less
expensively than the current generation of carbon-nanotube composites.
That opens the way for lighter, cheaper body armor, as well as lighter
auto bodies and airplane fuselages as well. Maybe "graphene golf-club
shafts" will become the status symbols of 2015.
Graphene in your touchscreen
If you make the graphene sheets thin enough, they basically become
transparent ... which has led some experts to suggest that the material
could be used in a new generation of low-cost, crack-resistant display
screens for televisions and laptops.
This year, researchers reported that they created a working touch-screen
display using graphene. Maybe the stuff will be ready for the market by
the time that future iPhone 9 is ready to pop.
Will graphene replace silicon?
There could be graphene inside the guts of that mobile device as well.
Geim and Novoselov pioneered the study of graphene's electronic effects,
but that work has been accelerating in the years since then. Electricity
flows easily through graphene without losing much energy along the way.
And scientists are finding ways to "dope" the material with other
elements, opening the way for ultra-thin, ultra-fast circuitry. This
year, IBM demonstrated a graphene-based transistor that operates 10 times
faster than the fastest silicon chip.
Maybe graphene is the thing that will keep Moore's Law going beyond the
current age of silicon.
The fast frequencies that can be achieved using graphene circuits are the
key to another potential application. "Graphene might emerge as a basis
for chemical sensors and for generators of terahertz-range light," Inside
Science News Service's Philip Schewe explains.
Terahertz radiation, or T-rays, are particularly well-suited for
detecting hidden objects at airport security checkpoints without the
health risk posed by X-rays. T-rays could also serve as the basis for
medical scanning devices that come even closer to the "Star Trek"
tricorder. T-ray scanning is already being used in Britain for skin-
cancer screening and tooth-cavity detection. Maybe graphene will hasten
the arrival of those brave new T-ray scanners, for better or worse.
Geim and Novoselov aren't in on all those applications, but their initial
Scotch-tape experiments along with the even more rigorous lab work that
followed are why they won a Nobel Prize today. So how long will it be
before all these graphene dreams turn into real products?
"I can only accurately predict the past, not the future," Geim told
"I would compare this situation with the one 100 years ago when people
discovered polymers. It took quite some time before polymers went into
use in plastics and became so important in our lives."
But it's a sure thing that graphene will eventually make an impact and
for that we have Geim and Novoselov to thank ..
To learn more about the Nobel-winning pair's achievement, check out the
background material from the Nobel Prize website, or read their detailed
scientific paper about "The Rise of Graphene." http://arxiv.org/ftp/cond-
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