Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Researchers love triangles: Shaped catalysts spark longer, faster-growing, rule-breaking nanowires

Abstract:
A research team at Case Western Reserve University has found that gold catalysts shaped in the form of a cube, triangle, or other higher order structures grow nanowires about twice as fast and twice as long compared to wires grown with the more typical spherically-shaped catalysts.

Researchers love triangles: Shaped catalysts spark longer, faster-growing, rule-breaking nanowires

Cleveland, OH | Posted on June 6th, 2012

This finding could prove useful to other scientists who are growing nanowires to build sensors fast enough to detect changes in red and white blood cells. These sensors in turn could help identify various forms of cancer in the body. The wires are so small - as small as one-5,000th the width of a human hair - they could also be used to build the next generation of "invisible" computer chips.

Xuan Gao, assistant professor of physics, and R. Mohan Sankaran, associate professor of chemical engineering, describe their work in the paper, "Shape-Controlled Au Particles for InAs Nanowire Growth," published in the journal Nano Letters.

Their research team included Case Western Reserve graduate students Pin Ann Lin and Dong Liang and Hathaway Brown Upper School student Samantha Reeves.

The researchers tested growth using both the preferentially-shaped and spherical catalysts under identical conditions to rule out error in the comparisons.

They suggest that the long accepted model of vapor-liquid-solid, or VLS, growth is incomplete, and that more tests are needed in order to fully understand the process.

Here's why: the researchers found that that the nanowires grown with the triangular catalyst have a much thicker layer of the metal Indium than the VLS nanowire growth model predicts.

The finding suggests a correlation between Indium concentration and growth enhancement. The team made the discovery when they beamed electrons at the nanowires to release high energy x-rays, a process called energy-dispersive X-ray spectroscopy. The magnitude of these energy bursts were used to determine chemical properties of the nanowires.

To grow nanowires, the researchers combined elements such as indium and arsenic, from rows 4 and 5 of the periodic table of elements. Elements from these rows bond to the gold particle to create a semiconductor that neither allows great flow of electric current nor greatly prevents its flow. This is called the "bottom-up method" which Gao describes as truly like "growing a plant from a seed."

Nanowires can also be made "top-down" with precise cuts on a large piece of semiconducting material, reducing it to a tiny structure of wires.

The disadvantage to this, Sankaran explains, is that cutting wires smaller than around 45 nm, which is the current standard in computer chips, "is impossible if we are using a machine. But if we were to grow the wires from chemical compounds we could make them as small as 10 nm, meaning we could fit more wires in a smaller space for greater speed."

However the bottom-up method only produces wires in bunches as opposed to the large interwoven structures made from the top-down method of cutting. The challenge is combining chemically-grown wires in ways that they work in complex electronics such as computer chips or highly-sensitive sensors.

Both Gao and Sankaran describe their research efforts as truly collaborative. Sankaran makes catalysts of different shapes to grow the nanowires, and Gao tests the properties of these wires and connects them to possible uses in the field.

This duo plans to continue exploring the correlation between catalyst shape and other structural characteristics of the wires in order to further develop the VLS model, and move closer to implementing nanowires in new technology.

Release prepared by Sean Linden, an undergraduate student at Case Western Reserve.

####

For more information, please click here

Contacts:
Kevin Mayhood

216-368-4442

Copyright © Case Western Reserve University

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

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

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

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanosafety research – there’s room for improvement October 29th, 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

Nanomedicine

'Electronic skin' could improve early breast cancer detection October 29th, 2014

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

Molecular beacons shine light on how cells 'crawl' October 27th, 2014

New nanodevice to improve cancer treatment monitoring October 27th, 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

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

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

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanoparticles Display Ability to Improve Efficiency of Filters October 28th, 2014

Announcements

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

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

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

Nanosafety research – there’s room for improvement October 29th, 2014

Research partnerships

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

Molecular beacons shine light on how cells 'crawl' October 27th, 2014

New evidence for an exotic, predicted superconducting state 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

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