Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > 'We're down to the atom size'

Abstract:
Cornell researchers discover how to focus on tiniest of the very small

'We're down to the atom size'

Posted on June 14, 2006

By Lauren Gold
lg34@cornell.edu

If you need a good picture of a molecule, your first job is getting its atoms to pose for you, says John Silcox, Cornell's David E. Burr Professor of Engineering and an expert in the realm of the very tiny.

But atoms are not willing subjects. They jiggle furiously, defying any microscopist who tries to catch them at a standstill. Nor are they polite: The larger atoms in a molecule typically overshadow the smaller ones, making it impossible to view the little ones.

Now, though, researchers at Cornell have developed a technique to get a closer-than-ever look at individual atoms within crystal molecules -- allowing them, for the first time, to see the polarity, or physical alignment, of those constituent atoms and to get a view of the smaller atoms.

The research -- by Cornell postdoctoral associate K. Andre Mkhoyan, Silcox and colleagues at Cornell, and Philip Batson of IBM -- is described in the June 2 issue of Science.

With the new technique, researchers can better predict the physical properties of a crystal at every point -- an advance that offers potential improvements in lasers and other devices, particularly at the nanoscale, where the structure of an individual molecule can determine a device's behavior.

To get their new and improved view, Mkhoyan's team used a scanning transmission electron microscope (STEM) at IBM on samples of aluminum nitride, gallium nitride and other crystals with particular significance in nanotechnology research, in a chamber padded and shielded to reduce potentially atom-jiggling acoustic noise and electromagnetic radiation. Fitting the STEM with an aberration corrector (a focusing device) developed at Nion Co., they directed a 0.9 angstroms-wide electron beam at tiny crystal samples, collecting the scattered electrons on a ring-shaped detector and forming an image based on the resulting scatter pattern. (An angstrom is one hundred-millionth of a centimeter). Because larger atoms deflect electrons at a larger angle than small ones, the resulting data is relatively simple to interpret.

Used on a sample of aluminum nitride, the technique, called annular dark imaging, shows pear-shaped molecule columns with the larger aluminum atoms at the thicker end and the smaller nitrogen atoms at the narrower end. It is the first time the smaller atoms in such a structure have been caught in an image.

The key, said Silcox, is the narrowness of the scanning electron beam.

"We're down to the atom size, as opposed to the atom spacing," said Silcox. "We can start to see the light atom columns; we can characterize the crystal very nicely and precisely, at every place on the structure."

Mkhoyan said the inability to capture such images in the past has been a huge hurdle for nanotechnology researchers.

"The study and application of these lattice crystals are at the core of nanotechnology. Many papers are dedicated to synthesis and application of the nanoparticles -- quantum dots, rods, wires, you name it -- based on these materials," he said. "However, the performance of the devices is highly dependent on the structural quality of these nanoparticles.

"With our STEM annular dark field imaging, we come to the rescue," Mkhoyan added. "We can zoom in, pick up any region of the structure, and see how it behaves."

####

Contact:
Cornell University News Service/Chronicle Online
312 College Ave.
Ithaca, NY 14850
607.255.4206
cunews@cornell.edu

Copyright Cornell 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

Materials/Metamaterials

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Self-healing tech charges up performance for silicon-containing battery anodes May 15th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

CCNY physicists demonstrate photonic hypercrystals for control of light-matter interaction May 5th, 2017

Announcements

Researchers find new way to control light with electric fields May 25th, 2017

Nanometrics Announces Retirement Plans of CEO Timothy Stultz: Dr. Stultz to Continue as Director May 25th, 2017

Nanomechanics, Inc. to Exhibit at the SEM Conference: Nanoindentation experts will attend and exhibit their instruments at the Conference and Exposition on Experimental and Applied Mechanics in Indianapolis May 25th, 2017

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Tools

Nanometrics Announces Retirement Plans of CEO Timothy Stultz: Dr. Stultz to Continue as Director May 25th, 2017

Nanomechanics, Inc. to Exhibit at the SEM Conference: Nanoindentation experts will attend and exhibit their instruments at the Conference and Exposition on Experimental and Applied Mechanics in Indianapolis May 25th, 2017

Plasmon-powered upconversion nanocrystals for enhanced bioimaging and polarized emission: Plasmonic gold nanorods brighten lanthanide-doped upconversion superdots for improved multiphoton bioimaging contrast and enable polarization-selective nonlinear emissions for novel nanoscal May 19th, 2017

The brighter side of twisted polymers: Conjugated polymers designed with a twist produce tiny, brightly fluorescent particles with broad applications May 16th, 2017

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