Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Spiraling nanotrees offer new twist on growth of nanowires

Abstract:
Since scientists first learned to make nanowires, the nano-sized wires just a few millionths of a centimeter thick have taken many forms, including nanobelts, nanocoils and nanoflowers.

Spiraling nanotrees offer new twist on growth of nanowires

Madison, WI | Posted on May 1st, 2008

But when University of Wisconsin-Madison chemistry professor Song Jin and graduate student Matthew Bierman accidentally made some pine tree shapes one day � complete with tall trunks and branches that tapered in length as they spiraled upward � they knew they�d stumbled upon something peculiar.

"At the beginning we saw just a couple of trees, and we said, "What the heck is going on here?" recalls Jin. "They were so curious."

Writing in the May 1 edition of Science Express, Jin and his team reveal just how curious the nanotrees truly are. In fact, they�re evidence of an entirely different way of growing nanowires, one that promises to give scientists a powerful means to create new and better nanomaterials for all sorts of applications, including high-performance integrated circuits, biosensors, solar cells, LEDs and lasers.

Until now, most nanowires have been made with metal catalysts, which promote the growth of nanomaterials along one dimension to form long rods. While the branches on Jin's trees also elongate in this way, growth of the trunks is driven by a 'screw' dislocation, or defect, in their crystal structure. At the top of the trunk, the defect provides a spiral step for atoms to settle on an otherwise perfect crystal face, causing them stack together in a spiral parking ramp-type structure that quickly lengthens the tip.

Dislocations are fundamental to the growth and characteristics of all crystalline materials, but this is the first time they've been shown to aid the growth of one-dimensional nanostructures. Engineering these defects, says Jin, may not only allow scientists to create more elaborate nanostructures, but also to investigate the fundamental mechanical, thermal and electronic properties of dislocations in materials.

His team created its nanotrees specifically by applying a slight variation of a synthesis technique called chemical vapor deposition to the material lead sulfide. But the chemists believe the new mechanism will be applicable to many other materials, as well.

"We think these findings will motivate a lot of people to do this purposefully, to design dislocation and try to grow nanowires around it," Jin says. "Or perhaps people who have grown a structure and were puzzled by it will read our paper and say, "Hey, we see something similar in our system, so maybe now we have the solution."

What initially puzzled Jin and his students about their pine tree structures was the long length of the trunks compared with the branches, a difference that indicated the trunks were growing much faster. The result was surprising because when complex, branching nanostructures are grown with metal catalysts, the branches are usually all of similar length because of similar growth rates, leading to boxy shapes rather than the cone-shapes of the trees.

Another oddity was the twist to the trunks, which sent the branches spiraling.

"The long and twisting trunks were telling us we had a new growth mode," says Jin. Suspecting dislocation, the team set about refining their technique for growing the pine trees - they soon learned to produce entire forests with ease - and then confirmed the presence of dislocations with a special type of transmission electron microscopy.

Upon closer examination, the twisting trunks and spiraling branches also turned out to embody a well-known general theory about the mechanical deformation of crystalline materials caused by screw dislocations. Although this so-called 'Eshelby twist' was first calculated back in 1953 and is discussed in many textbooks, Jin's experimental results likely offer the best support yet for the theory.

"These are beautiful, truly intriguing structures, but behind them is also a really beautiful, interesting science," says Jin. "Once you understand it, you just feel so satisfied."


The paper's other authors are Y.K. Albert Lau, Alexander Kvit and Andrew Schmitt. The work was funded by the National Science Foundation.

####

For more information, please click here

Contacts:
Song Jin

608-262-1562

Copyright © University of Wisconsin-Madison

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Small but heading for the big time: Nanobiotix half year results for the six months ended 30 June 2015, in line with expectations: Major clinical achievements and corporate developments August 28th, 2015

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

Nanolab Technologies LEAPS Forward with High-Performance Analysis Services to the World: Nanolab Orders Advanced Local Electrode Atom Probe (LEAP®) Microscope from CAMECA Unit of AMETEK Materials Analysis Division August 27th, 2015

Display technology/LEDs/SS Lighting/OLEDs

'Quantum dot' technology may help light the future August 19th, 2015

High-precision control of nanoparticles for digital applications August 19th, 2015

Flexible, biodegradable device can generate power from touch (video) August 12th, 2015

New research may enhance display & LED lighting technology: Large-area integration of quantum dots and photonic crystals produce brighter and more efficient light August 9th, 2015

Chip Technology

Nanometrics to Participate in the Citi 2015 Global Technology Conference August 26th, 2015

Kwansei Gakuin University in Hyogo, Japan, uses Raman microscopy to study crystallographic defects in silicon carbide wafers August 25th, 2015

A little light interaction leaves quantum physicists beaming August 25th, 2015

'Magic' sphere for information transfer: Professor at the Lomonosov Moscow State University made the «magic» sphere for information transfer August 24th, 2015

Sensors

Successful boron-doping of graphene nanoribbon August 27th, 2015

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

High Precision, High Stability XYZ Microscope Stages, with Capacitive Feedback August 18th, 2015

Setting ground rules for nanotechnology research: Two new projects set the stage for nanotechnology research to move into Big Data August 18th, 2015

Nanoelectronics

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

'Quantum dot' technology may help light the future August 19th, 2015

Surprising discoveries about 2-D molybdenum disulfide: Berkeley Lab researchers use award-winning campanile probe on promising semiconductor August 15th, 2015

Better together: Graphene-nanotube hybrid switches August 3rd, 2015

Discoveries

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

CWRU researchers efficiently charge a lithium-ion battery with solar cell: Coupling with perovskite solar cell holds potential for cleaner cars and more August 27th, 2015

Successful boron-doping of graphene nanoribbon August 27th, 2015

Announcements

Small but heading for the big time: Nanobiotix half year results for the six months ended 30 June 2015, in line with expectations: Major clinical achievements and corporate developments August 28th, 2015

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

Nanolab Technologies LEAPS Forward with High-Performance Analysis Services to the World: Nanolab Orders Advanced Local Electrode Atom Probe (LEAP®) Microscope from CAMECA Unit of AMETEK Materials Analysis Division August 27th, 2015

Photonics/Optics/Lasers

Glitter from silver lights up Alzheimer's dark secrets August 25th, 2015

Quantum diffraction at a breath of nothing: Physicists build stable diffraction structure in atomically thin graphene August 25th, 2015

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

A little light interaction leaves quantum physicists beaming August 25th, 2015

Solar/Photovoltaic

CWRU researchers efficiently charge a lithium-ion battery with solar cell: Coupling with perovskite solar cell holds potential for cleaner cars and more August 27th, 2015

Novel nanostructures for efficient long-range energy transport August 21st, 2015

Charge transport in hybrid silicon solar cells August 17th, 2015

Nano Electrolyte Additives Increase Efficiency of Solar Cells August 10th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic