Featured Research

from universities, journals, and other organizations

Graphene: What can go wrong? New studies point to wrinkles, process contaminants

Date:
July 8, 2011
Source:
National Institute of Standards and Technology (NIST)
Summary:
Using a combination of sophisticated computer modeling and advanced materials analysis techniques at synchrotron laboratories, a research team has demonstrated how some relatively simple processing flaws can seriously degrade the otherwise near-magical electronic properties of graphene.

Using a combination of sophisticated computer modeling and advanced materials analysis techniques at synchrotron laboratories, a research team led by the University at Buffalo (UB) and including the National Institute of Standards and Technology (NIST), the Molecular Foundry at Lawrence Berkeley National Laboratory and SEMATECH has demonstrated how some relatively simple processing flaws can seriously degrade the otherwise near-magical electronic properties of graphene.

Their new paper demonstrates how both wrinkles in the graphene sheet and/or chance contaminants from processing -- possibly hiding in those folds -- disrupt and slow electron flow across the sheet. The results could be important for the design of commercial manufacturing processes that exploit the unique electrical properties of graphene. In the case of contaminant molecules at least, the paper also suggests that heating the graphene may be a simple solution.

Graphene, a nanostructured material that is essentially a one-atom thick sheet of carbon atoms arranged in a hexagonal pattern, is under intense study because of a combination of outstanding properties. It's extremely strong, conducts heat very well, and has high electrical conductivity while being flexible and transparent. Graphene's electrical properties, however, apparently depend a lot on flatness and purity.

Using X-rays, the UB team produced images that show the electron "cloud" lining the surface of graphene samples -- the structure responsible for the high-speed transit of electrons across the sheet -- and how wrinkles in the sheet distort the cloud and create bottlenecks. Spectrographic data showed anomalous "peaks" in some regions that also corresponded to distortions of the cloud. NIST researchers, using their dedicated materials science "beam line" at the National Synchrotron Light Source (NSLS), contributed a sensitive analysis of spectroscopic data confirming that these peaks were caused by chemical contaminants that adhered to the graphene during processing.

Significantly, the NIST synchrotron methods group was able to make detailed spectroscopic measurements of the graphene samples while heating them, and found that the mysterious peaks disappeared by the time the sample reached 150 degrees Celsius. This, according to Dan Fischer, leader of the NIST group, showed both that those particular disturbances in the electron cloud were due to contaminants, and that there is a way to get rid of them. "They're not chemical bound, they're just physically absorbed on the surface, and that's an important thing. You have a prescription for getting rid of them," Fischer said.

"When graphene was discovered, people were just so excited that it was such a good material that people really wanted to go with it and run as fast as possible," said Brian Schultz, one of three UB graduate students who were lead authors on the paper, "but what we're showing is that you really have to do some fundamental research before you understand how to process it and how to get it into electronics."

"This is the practical side of using graphene," agrees Fischer, "It has all these remarkable properties, but when you go to actually try to make something, maybe they stop working, and the question is: why and what do you do about it? These kinds of extremely sensitive, specialized techniques are part of that answer."


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Brian J. Schultz, Christopher J. Patridge, Vincent Lee, Cherno Jaye, Patrick S. Lysaght, Casey Smith, Joel Barnett, Daniel A. Fischer, David Prendergast, Sarbajit Banerjee. Imaging local electronic corrugations and doped regions in graphene. Nature Communications, 2011; 2: 372 DOI: 10.1038/ncomms1376

Cite This Page:

National Institute of Standards and Technology (NIST). "Graphene: What can go wrong? New studies point to wrinkles, process contaminants." ScienceDaily. ScienceDaily, 8 July 2011. <www.sciencedaily.com/releases/2011/07/110707111045.htm>.
National Institute of Standards and Technology (NIST). (2011, July 8). Graphene: What can go wrong? New studies point to wrinkles, process contaminants. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2011/07/110707111045.htm
National Institute of Standards and Technology (NIST). "Graphene: What can go wrong? New studies point to wrinkles, process contaminants." ScienceDaily. www.sciencedaily.com/releases/2011/07/110707111045.htm (accessed August 29, 2014).

Share This




More Matter & Energy News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. 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