Featured Research

from universities, journals, and other organizations

Toward better electronics: Researchers develop new way to oxidize promising graphene

Date:
February 19, 2012
Source:
Northwestern University
Summary:
Many experts think graphene could change the face of electronics -- especially if the scientific community can overcome a major challenge intrinsic to the material. Oxidation could be the answer.

Artist's rendering of graphene.
Credit: Dmitry Knorre / Fotolia

Researchers at Northwestern University have developed a new method for chemically altering graphene, a development that could be a step toward the creation of faster, thinner, flexible electronics.

Highly desired for its many promising attributes, graphene is a one-atom thick, honeycomb-shaped lattice of carbon atoms with exceptional strength and conductivity. Among graphene's many possible applications is electronics: Many experts believe it could rival silicon, transforming integrated circuits and leading to ultra-fast computers, cellphones and related portable electronic devices.

But first, researchers must learn how to tune the electronic properties of graphene -- not an easy feat, given a major challenge intrinsic to the material. Unlike semiconductors such as silicon, pure graphene is a zero band-gap material, making it difficult to electrically "turn off" the flow of current through it. Therefore, pristine graphene is not appropriate for the digital circuitry that comprises the vast majority of integrated circuits.

To overcome this problem and make graphene more functional, researchers around the world are investigating methods for chemically altering the material. The most prevalent strategy is the "Hummers method," a process developed in the 1940s that oxidizes graphene, but that method relies upon harsh acids that irreversibly damage the fabric of the graphene lattice.

Researchers at Northwestern's McCormick School of Engineering and Applied Science have recently developed a new method to oxidize graphene without the collateral damage encountered in the Hummers method. Their oxidation process is also reversible, which enables further tunability over the resulting properties of their chemically modified graphene.

The paper, "Chemically Homogeneous and Thermally Reversible Oxidation of Epitaxial Graphene," is published Feb. 19 by the journal Nature Chemistry.

"Performing chemical reactions on graphene is very difficult," said Mark C. Hersam, professor of materials science and engineering at the McCormick School. "Typically, researchers employ aggressive acidic conditions, such as those utilized in the Hummers method, that damage the lattice and result in a material that is difficult to control.

"In our method, however, the resulting graphene oxide is chemically homogeneous and reversible -- leading to well-controlled properties that can likely be exploited in high-performance applications," said Hersam, who is also a professor of chemistry and of medicine.

To create the graphene oxide, researchers leaked oxygen gas (O2) into an ultra-high vacuum chamber. Inside, a hot tungsten filament was heated to 1500 degrees Celsius, causing the oxygen molecules to dissociate into atomic oxygen. The highly reactive oxygen atoms then uniformly inserted into the graphene lattice.

The resulting material possesses a high degree of chemical homogeneity. Spectroscopic measurements show that the electronic properties of the graphene vary as a function of oxygen coverage, suggesting that this approach can tune the properties of graphene-based devices.

"It's unclear if this work will impact real-world applications overnight," Hersam said. "But it appears to be a step in the right direction."

Next, researchers will explore other means of chemically modifying graphene to develop a wider variety of materials, much like scientists did for plastics in the last century.

"Maybe oxygen isn't enough," Hersam said. "Through chemical modification, the scientific community has developed a wide range of polymers, from hard plastics to nylon. We hope to realize the same degree of tunability for graphene."

The National Science Foundation, the Office of Naval Research and the U.S. Department of Energy supported the research.


Story Source:

The above story is based on materials provided by Northwestern University. The original article was written by Sarah Ostman, content specialist at the McCormick School of Engineering and Applied Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Md. Zakir Hossain, James E. Johns, Kirk H. Bevan, Hunter J. Karmel, Yu Teng Liang, Shinya Yoshimoto, Kozo Mukai, Tatanori Koitaya, Jun Yoshinobu, Maki Kawai, Amanda M. Lear, Larry L. Kesmodel, Steven L. Tait, Mark C. Hersam. Chemically homogeneous and thermally reversible oxidation of epitaxial graphene. Nature Chemistry, 2012; DOI: 10.1038/nchem.1269

Cite This Page:

Northwestern University. "Toward better electronics: Researchers develop new way to oxidize promising graphene." ScienceDaily. ScienceDaily, 19 February 2012. <www.sciencedaily.com/releases/2012/02/120219143325.htm>.
Northwestern University. (2012, February 19). Toward better electronics: Researchers develop new way to oxidize promising graphene. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/02/120219143325.htm
Northwestern University. "Toward better electronics: Researchers develop new way to oxidize promising graphene." ScienceDaily. www.sciencedaily.com/releases/2012/02/120219143325.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com
U.K. To Allow Driverless Cars On Public Roads

U.K. To Allow Driverless Cars On Public Roads

Newsy (July 30, 2014) Driverless cars could soon become a staple on U.K. city streets, as they're set to be introduced to a few cities in 2015. Video provided by Newsy
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