Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > 'Tuning' Graphene Drums Might Turn Conductors to Semiconductors

NIST researchers showed that straining graphene membrane creates pseudomagnetic fields that confines the graphene's electrons and creates quantized quantum dot-like energy levels. The background is a false color image of the graphene drumheads made from a single layer of graphene over 1 micron-sized pits etched in a silicon dioxide substrate.
Credit: N. Klimov and T. Li, NIST/UMD
NIST researchers showed that straining graphene membrane creates pseudomagnetic fields that confines the graphene's electrons and creates quantized quantum dot-like energy levels. The background is a false color image of the graphene drumheads made from a single layer of graphene over 1 micron-sized pits etched in a silicon dioxide substrate.

Credit: N. Klimov and T. Li, NIST/UMD

Abstract:
Tightening or relaxing the tension on a drumhead will change the way the drum sounds. The same goes for drumheads made from graphene, only instead of changing the sound, stretching graphene dramatically alters the material's electrical properties. Researchers working at the National Institute of Standards and Technology (NIST) and the University of Maryland have shown* that subjecting graphene to mechanical strain can mimic the effects of magnetic fields and create a quantum dot, an exotic type of semiconductor with a wide range of potential uses in electronic devices.

'Tuning' Graphene Drums Might Turn Conductors to Semiconductors

Gaithersburg, MD | Posted on June 28th, 2012

Graphene is a single layer of carbon atoms arranged in a honeycomb lattice. Pure graphene is a phenomenal conductor, transmitting electricity with little resistance at room temperature. But microelectronic devices depend on semiconductors that can be turned "on" and "off" because they have an energetic threshold beneath which they won't conduct electricity. This new work demonstrates that mechanical strain can be used to make tiny regions of graphite act like a classic semiconductor.

The research team suspended a sheet of graphene over shallow holes in a substrate of silicon dioxide—essentially making a set of graphene drumheads. In probing the drumheads with a scanning probe microscope, they found that the graphene rose up to meet the tip of the microscope— a result of the van der Waals force, a weak electrical force that creates attraction between objects that are very close to each other. Calculations by the University of Maryland group showed that the graphene should stretch into a peak, like the top of a circus tent.

The researchers discovered that they could tune the strain in the drumhead using the conducting plate upon which the graphene and substrate were mounted to create a countervailing attraction and pull the drumhead down. In this way, they could pull the graphene into or out of the hole below it.

Their measurements showed that changing the degree of strain changed the material's electrical properties. When they pulled the graphene membrane into the tent-like shape, the region at the apex acted just like a quantum dot, a type of semiconductor in which electrons are confined to a small region of space.

"Normally, to make a graphene quantum dot, you would have to cut out a nanosize piece of graphene," says NIST fellow Joseph Stroscio. "Our work shows that you can achieve the same thing with strain-induced pseudomagnetic fields. It's a great result, and a significant step toward developing future graphene-based devices."

More details are available in the June 21 NIST news announcement, "Graphene Drumheads Tuned to Make Quantum Dots" at www.nist.gov/cnst/drumheads_062112.cfm.

The work was a collaborative effort with the University of Maryland, College Park, and the Korea Research Institute of Standards and Science.

* N. Klimov, S. Jung, S. Zhu, T. Li, C. Wright, S. Solares, D. Newell, N. Zhitenev and J. Stroscio. Electromechanical properties of graphene drumheads. Science. Vol. 336 no. 6088 pp. 1557-1561 DOI: 10.1126/science.1220335. Published online before print June 21, 2012.

####

About National Institute of Standards and Technology (NIST)
The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

For more information, please click here

Contacts:
Mark Esser
301-975-8735

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Graphene/ Graphite

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Laboratories

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Govt.-Legislation/Regulation/Funding/Policy

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Chip Technology

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Nanometrics Reports Second Quarter 2016 Financial Results July 26th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Discoveries

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Announcements

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Ultrasensitive sensor using N-doped graphene July 26th, 2016

Quantum Dots/Rods

Researchers develop faster, precise silica coating process for quantum dot nanorods July 12th, 2016

Building a better bowtie: Bowtie-shaped nanostructures may advance the development of quantum devices WEIZMANN July 5th, 2016

A new form of hybrid photodetectors with quantum dots and graphene June 19th, 2016

Supercrystals with new architecture can enhance drug synthesis May 24th, 2016

Research partnerships

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Ultrasensitive sensor using N-doped graphene July 26th, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Rice's 'antenna-reactor' catalysts offer best of both worlds: Technology marries light-harvesting nanoantennas to high-reaction-rate catalysts July 18th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic