The
nanowire, which is about
1000 times thinner than a human hair, is so strong it
could support 16 African elephants if it was scaled up to the size of a child's finger, says Sader.
:eek:
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World's strongest
nanowire
Scientists say they have made the world's strongest nanowire, reaching the theoretical limits of what they'd planned to build.
The nanowire, which is about 1000 times thinner than a human hair, is so strong it could support 16 African elephants if it was scaled up to the size of a child's finger, says Associate Professor John Sader from Australia's
University of Melbourne.
Sader is part of an international team of scientists that grew the semiconducting nanomaterial, publishing the results in the journal
Nano Letters.
"The ultimate strength we report is the highest recorded for any semiconductor material system and is at the theoretically predicted limit," says Sader, who was involved in measuring the strength of the wires using an atomic force microscope.
"This indicates that these nanowires are near perfect materials."
Experts say that such nanowires could one day be used to make electrical and electromechanical devices like environmental sensors or even ultra-precise clocks.
To built a nanowire
The nanowires were built from germanium, an element the researchers say has similar chemical properties to tin.
They built the material on a surface coated with gold nanocrystals, which allowed the germanium to nucleate and grow.
They then tested the strength by placing it across a small trench and manipulating it sideways.
They found it could bend and stretch further than any other nanowire anyone had ever made, sustaining 15 gigapascals before snapping.
This was roughly the same as the predicted ultimate force, compared to many other semiconducting nanowires, which snap at just 15% of their theoretical limits.
If the wire was one centimetre in diameter it could hold up to 100 tonnes without breaking, he says.
This resilience will result in failproof nanodevices, says Sader, adding it is not theoretically possible to make a stronger nanowire.
"This exhibits the theoretical limits, so this is basically it," he says.
Tuning forks and metronomes
Professor Paul Mulvaney from the University of Melbourne's school of chemistry, who wasn't involved in the research, says the nanowires could be used as sensors to detect gases, air pollutants or biological agents.
This is because they function as super-sensitive 'tuning forks' that change frequency when molecules become attached to them.
"Because the wires are so small, they can detect very small amounts of materials absorbing onto their surface," he says.
They could also be used as nanoscale metronomes that vibrate in high-frequency timing devices or in computer chips, he says.
Germanium nanowires are also ideal candidates for making optical devices like light-emitting diodes and tuneable lasers, Mulvaney says.
http://www.ms.unimelb.edu.au/AboutUs/news.php