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:10/10/2017)... ... October 10, 2017 , ... ... conjugate (ADC) therapeutics, today confirmed licensing rights that give it exclusive global ... technology developed in collaboration with Children’s Hospital Los Angeles (CHLA). Additionally, ...
(Date:10/10/2017)... ... ... Dr. Bob Harman, founder and CEO of VetStem Biopharma, Inc. spent ... entitled “Stem Cells and Their Regenerative Powers,” was held on August 31st, 2017 ... joined by two human doctors: Peter B. Hanson, M.D., Chief of Orthopedic Surgery, Grossmont ...
(Date:10/10/2017)... CRUZ, Calif. , Oct. 10, 2017 ... grant from the NIH to develop RealSeq®-SC (Single Cell), ... kit for profiling small RNAs (including microRNAs) from single ... Analysis Program highlights the need to accelerate development of ... "New techniques for measuring ...
(Date:10/10/2017)... ... October 10, 2017 , ... The Pittcon Program Committee ... honoring scientists who have made outstanding contributions to analytical chemistry and applied ... the world’s leading conference and exposition for laboratory science, which will be held ...
Breaking Biology Technology:
(Date:4/11/2017)... Research and Markets has announced the addition ... their offering. ... tracking market to grow at a CAGR of 30.37% during the ... 2017-2021, has been prepared based on an in-depth market analysis with ... its growth prospects over the coming years. The report also includes ...
(Date:4/5/2017)... 5, 2017 Today HYPR Corp. , ... server component of the HYPR platform is officially ... end-to-end security architecture that empowers biometric authentication across Fortune ... already secured over 15 million users across the financial ... connected home product suites and physical access represent a ...
(Date:3/30/2017)... The research team of The Hong Kong ... identification by adopting ground breaking 3D fingerprint minutiae recovery and matching ... and accuracy for use in identification, crime investigation, immigration control, security ... ... A research team led by ...
Breaking Biology News(10 mins):