Navigation Links
Graphene yields secrets to its extraordinary properties
Date:5/14/2009

Applying innovative measurement techniques, researchers from the Georgia Institute of Technology and the National Institute of Standards and Technology (NIST) have directly measured the unusual energy spectrum of graphene, a technologically promising, two-dimensional form of carbon that has tantalized and puzzled scientists since its discovery in 2004.

Published in this week's issue of Science,* their work adds new detail to help explain the unusual physical phenomena and properties associated with graphene, a single layer of carbon atoms arrayed in a repeating, honeycomb-like arrangement.

Graphene's exotic behaviors present intriguing prospects for future technologies, including high-speed, graphene-based electronics that might replace today's silicon-based integrated circuits and other devices. Even at room temperature, electrons in graphene are more than 100 times more mobile than in silicon.

Graphene apparently owes this enhanced mobility to the curious fact that its electrons and other carriers of electric charges behave as though they do not have mass. In conventional materials, the speed of electrons is related to their energy, but not in graphene. Although they do not approach the speed of light, the unbound electrons in graphene behave much like photons, massless particles of light that also move at a speed independent of their energy.

This weird massless behavior is associated with other strangeness. When ordinary conductors are put in a strong magnetic field, charge carriers such as electrons begin moving in circular orbits that are constrained to discrete, equally spaced energy levels. In graphene these levels are known to be unevenly spaced because of the "massless" electrons.

The Georgia Tech/NIST team tracked these massless electrons in action, using a specialized NIST instrument to zoom in on the graphene layer at a billion times magnification, tracking the electronic states while at the same time applying high magnetic fields. The custom-built, ultra-low-temperature and ultra-high-vacuum scanning tunneling microscope allowed them to sweep an adjustable magnetic field across graphene samples prepared at Georgia Tech, observing and mapping the peculiar non-uniform spacing among discrete energy levels that form when the material is exposed to magnetic fields.

The team developed a high-resolution map of the distribution of energy levels in graphene. In contrast to metals and other conducting materials, where the distance from one energy peak to the next is uniformly equal, this spacing is uneven in graphene.

The researchers also probed and spatially mapped graphene's hallmark "zero energy state," a curious phenomenon where the material has no electrical carriers until a magnetic field is applied.

The measurements also indicated that layers of graphene grown and then heated on a substrate of silicon-carbide behave as individual, isolated, two-dimensional sheets. On the basis of the results, the researchers suggest that graphene layers are uncoupled from adjacent layers because they stack in different rotational orientations. This finding may point the way to manufacturing methods for making large, uniform batches of graphene for a new carbon-based electronics.


'/>"/>

Contact: Mark Bello
mark.bello@nist.gov
301-975-3776
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology technology :

1. UM physicists show electrons can travel over 100 times faster in graphene than in silicon
2. Graphene gazing gives glimpse of foundations of universe
3. Graphene used to create worlds smallest transistor
4. Graphene-based gadgets may be just years away
5. By adding graphene, researchers create superior polymer
6. Penn scientists demonstrate potential of graphene films as next-generation transistors
7. Graphene pioneers follow in Nobel footsteps
8. New graphene-based material clarifies graphite oxide chemistry
9. Researchers discover method for mass production of nanomaterial graphene
10. Light-speed nanotech: Controlling the nature of graphene
11. Scientists prove graphenes edge structure affects electronic properties
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/23/2016)... Lawrence, MA (PRWEB) , ... June 23, 2016 ... ... the Peel Plate® YM (Yeast and Mold) microbial test has received AOAC Research ... test platform of microbial tests introduced last year,” stated Bob Salter, Vice President ...
(Date:6/23/2016)... ... ... Supplyframe, the Industry Network for electronics hardware design and ... in Pasadena, Calif., the Design Lab’s mission is to bring together inventors and ... brought to market. , The Design Lab is Supplyframe’s physical representation of one ...
(Date:6/23/2016)... NEWPORT BEACH, Calif. , June 23, 2016 /PRNewswire/ ... offering new biological discoveries to the medical community, has ... and co-founder Matthew Nunez . "We ... provide us with the capital we need to meet ... funding will essentially provide us the runway to complete ...
(Date:6/23/2016)... Pleasant Prairie, WI (PRWEB) , ... June 23, ... ... sciences consultancy focused on quality, regulatory and technical consulting, provides a free ... webinar is presented on July 13, 2016 at 12pm CT at no charge. ...
Breaking Biology Technology:
(Date:6/2/2016)... LONDON , June 2, 2016 ... has awarded the 44 million US Dollar project, ... Security Embossed Vehicle Plates including Personalization, Enrolment, and IT Infrastructure ... world leader in the production and implementation of Identity Management ... in January, however Decatur was selected ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is excited ... with VoicePass. By working together, VoiceIt ...  Because VoiceIt and VoicePass take slightly different approaches ... increases both security and usability. ... about this new partnership. "This marketing ...
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 ... subsidiary of Infosys (NYSE: INFY ), and Samsung ... global partnership that will provide end customers with a ... and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... for financial services, but it also plays a fundamental part ...
Breaking Biology News(10 mins):