Featured Research

from universities, journals, and other organizations

Researchers Discover How To Focus On Tiniest Of The Very Small

Date:
June 20, 2006
Source:
Cornell University
Summary:
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 physical alignment of those constituent atoms and to get a view of the smaller atoms.

This image of a lattice crystal was captured by Cornell researchers using a scanning transmission electron microscope (STEM) at IBM. The yellow circles in the center of each pear-shaped molecule represent the stronger signal produced by a large atom; the red portions that make up the top of each pear shape show the weaker signal of the smaller atoms. The image allows researchers to see the orientation of the individual atoms within a crystal for the first time, thus giving researchers a vital tool for predicting the crystal's properties. A model of the molecular structure is superimposed on the image.
Credit: Image courtesy of Cornell University

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."


Story Source:

The above story is based on materials provided by Cornell University. Note: Materials may be edited for content and length.


Cite This Page:

Cornell University. "Researchers Discover How To Focus On Tiniest Of The Very Small." ScienceDaily. ScienceDaily, 20 June 2006. <www.sciencedaily.com/releases/2006/06/060620081234.htm>.
Cornell University. (2006, June 20). Researchers Discover How To Focus On Tiniest Of The Very Small. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2006/06/060620081234.htm
Cornell University. "Researchers Discover How To Focus On Tiniest Of The Very Small." ScienceDaily. www.sciencedaily.com/releases/2006/06/060620081234.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins