Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

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

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Amorphous Coordination Polymer Particles as alternative to classical nanoplatforms for nanomedicine October 30th, 2014

Display technology/LEDs/SS Lighting/OLEDs

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

QD Vision Wins Prestigious Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency October 16th, 2014

Beyond LEDs: Brighter, new energy-saving flat panel lights based on carbon nanotubes - Planar light source using a phosphor screen with highly crystalline single-walled carbon nanotubes (SWCNTs) as field emitters demonstrates its potential for energy-efficient lighting device October 14th, 2014

Aledia’s Nanowire LED Technology Endorsed By 2014 Physics Nobel Prize Winner: Hiroshi Amano Serves on Company’s Scientific Advisory Board October 13th, 2014

Chip Technology

Sussex physicists find simple solution for quantum technology challenge October 28th, 2014

Watching the hidden life of materials: Ultrafast electron diffraction experiments open a new window on the microscopic world October 27th, 2014

Breakthrough in molecular electronics paves the way for DNA-based computer circuits in the future: DNA-based programmable circuits could be more sophisticated, cheaper and simpler to make October 27th, 2014

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

Sensors

Tiny carbon nanotube pores make big impact October 29th, 2014

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Journal Nanotechnology Progress International (JONPI), 2014, Volume 5, Issue 1, pp 1-24 October 22nd, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Nanoelectronics

Breakthrough in molecular electronics paves the way for DNA-based computer circuits in the future: DNA-based programmable circuits could be more sophisticated, cheaper and simpler to make October 27th, 2014

NIST offers electronics industry 2 ways to snoop on self-organizing molecules October 22nd, 2014

Materials for the next generation of electronics and photovoltaics: MacArthur Fellow develops new uses for carbon nanotubes October 21st, 2014

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Discoveries

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Amorphous Coordination Polymer Particles as alternative to classical nanoplatforms for nanomedicine October 30th, 2014

Announcements

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Amorphous Coordination Polymer Particles as alternative to classical nanoplatforms for nanomedicine October 30th, 2014

Photonics/Optics/Lasers

Watching the hidden life of materials: Ultrafast electron diffraction experiments open a new window on the microscopic world October 27th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

IRLYNX and CEA-Leti to Streamline New CMOS-based Infrared Sensing Modules Dedicated to Human-activities Characterization October 15th, 2014

Solar/Photovoltaic

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Advancing thin film research with nanostructured AZO: Innovnano’s unique and cost-effective AZO sputtering targets for the production of transparent conducting oxides October 23rd, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

Dyesol Signs Letter of Intent with Tata Steel October 13th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE