Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Playing pool with carbon atoms: UA physicists discover how to change the crystal structure of graphene

Using a sharp metal scanning tunneling microscopy tip, LeRoy and his collaborators were able to move the domain border between the two graphene configurations around.

Credit: Pablo San-Jose ICMM-CSI
Using a sharp metal scanning tunneling microscopy tip, LeRoy and his collaborators were able to move the domain border between the two graphene configurations around.

Credit: Pablo San-Jose ICMM-CSI

Abstract:
A University of Arizona-led team of physicists has discovered how to change the crystal structure of graphene, more commonly known as pencil lead, with an electric field, an important step toward the possible use of graphene in microprocessors that would be smaller and faster than current, silicon-based technology.

Playing pool with carbon atoms: UA physicists discover how to change the crystal structure of graphene

Tucson, AZ | Posted on April 30th, 2014

Graphene consists of extremely thin sheets of graphite: when writing with a pencil, graphene sheets slough off the pencil's graphite core and stick to the page. If placed under a high-powered electron microscope, graphene reveals its sheet-like structure of cross-linked carbon atoms, resembling chicken wire.

When manipulated by an electric field, parts of the material are transformed from behaving as a metal to behaving as a semiconductor, the UA physicists found.

Graphene is the world's thinnest material, with 300,000 sheets needed to amount to the thickness of a human hair or a sheet of paper. Scientists and engineers are interested in it because of its possible applications in microelectronic devices, in hopes of propelling us from the silicon age to the graphene age. The tricky part is to control the flow of electrons through the material, a necessary prerequisite for putting it to work in any type of electronic circuit.

Brian LeRoy, UA associate professor of physics, and his collaborators have cleared a hurdle toward that goal by showing that an electric field is capable of controlling the crystal structure of trilayer graphene - which is made up of three layers of graphene.

Most materials require high temperatures, pressure or both to change their crystal structure, which is the reason why graphite doesn't spontaneously turn into diamond or vice versa.

"It is extremely rare for a material to change its crystal structure just by applying an electric field," LeRoy said. "Making trilayer graphene is an exceptionally unique system that could be utilized to create novel devices."

Trilayer graphene can be stacked in two unique ways. This is analogous to stacking layers of billiards balls in a triangular lattice, with the balls representing the carbon atoms.

"When you stack two layers of billiards balls, their 'crystal structure' is fixed because the top layer of balls must sit in holes formed by the triangles of the bottom layer," explained Matthew Yankowitz, a third-year doctoral student in LeRoy's lab. He is the first author on the published research, which appears in the journal Nature Materials. "The third layer of balls may be stacked in such a way that its balls are flush above the balls in the bottom layer, or it may be offset slightly so its balls come to lie above the holes formed by triangles in the bottom layer."

These two stacking configurations can naturally exist in the same flake of graphene. The two domains are separated by a sharp boundary where the carbon hexagons are strained to accommodate the transition from one stacking pattern to the other.

"Due to the different stacking configurations on either side of the domain wall, one side of the material behaves as a metal, while the other side behaves as a semiconductor," LeRoy explained.

While probing the domain wall with an electric field, applied by an extremely sharp metal scanning tunneling microscopy tip, the researchers in LeRoy's group discovered that they could move the position of the domain wall within the flake of graphene. And as they moved the domain wall, the crystal structure of the trilayer graphene changed in its wake.

"We had the idea that there would be interesting electronic effects at the boundary, and the boundary kept moving around on us," LeRoy said. "At first it was frustrating, but once we realized what was going on, it turned out to be the most interesting effect."

By applying an electric field to move the boundary, it is now possible for the first time to change the crystal structure of graphene in a controlled fashion.

"Now we have a knob that we can turn to change the material from metallic into semiconducting and vice versa to control the flow of electrons," LeRoy said. "It basically gives us an on-off switch, which had not been realized yet in graphene."

While more research is needed before graphene can be applied in technological applications on an industrial scale, researchers see ways it may be used.

"If you used a wide electrode instead of a pointed tip, you could move the boundary between the two configurations a farther distance, which could make it possible to create transistors from graphene," Yankowitz said.

Transistors are a staple of electronic circuits because they control the flow of electrons.

Unlike silicon transistors used now, graphene-based transistors could be extremely thin, making the device much smaller, and since electrons move through graphene much faster than through silicon, the devices would enable faster computing.

In addition, silicon-based transistors are being manufactured to function as one of two types - p-type or n-type - whereas graphene could operate as both. This would make them cheaper to produce and more versatile in their applications.

###

The other contributors to the research paper, "Electric field control of soliton motion and stacking in trilayer graphene," include Joel I-Jan Wang (Massachusetts Institute of Technology and Harvard University in Cambridge, Massachusetts), A. Glen Birdwell (U.S. Army Research Laboratory, Adelphi, Maryland), Yu-An Chen (MIT), K. Watanabe and T. Taniguchi (National Institute for Materials Science, Tsukuba, Japan), Philippe Jacquod (UA Department of Physics), Pablo San-Jose (Instituto de Ciencia de Materiales de Madrid) and Pablo Jarillo-Herrero (MIT).

####

For more information, please click here

Contacts:
Daniel Stolte

520-626-4402

Copyright © University of Arizona

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 Links

The study appears in the advance online publication of Nature Materials at:

Related News Press

News and information

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Arrowhead to Present at Jefferies 2015 Healthcare Conference May 27th, 2015

Seeing the action: UCSB researchers develop a novel device to image the minute forces and actions involved in cell membrane hemifusion May 27th, 2015

Laboratories

Collaboration could lead to biodegradable computer chips May 28th, 2015

Engineering Phase Changes in Nanoparticle Arrays: Scientists alter attractive and repulsive forces between DNA-linked particles to make dynamic, phase-shifting forms of nanomaterials May 25th, 2015

Visualizing How Radiation Bombardment Boosts Superconductivity: Atomic-level flyovers show how impact sites of high-energy ions pin potentially disruptive vortices to keep high-current superconductivity flowing May 23rd, 2015

Graphene

Dr.Theivasanthi Slashes the Price of Graphene Heavily: World first & lowest price – Nano-price (30 USD / kg) of graphene by nanotechnologist May 26th, 2015

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

Govt.-Legislation/Regulation/Funding/Policy

Collaboration could lead to biodegradable computer chips May 28th, 2015

Nanotechnology identifies brain tumor types through MRI 'virtual biopsy' in animal studies: If results are confirmed in humans, tumor cells could someday be diagnosed by MRI imaging and treated with tumor-specific IV injections; new NIH grant will fund future study May 27th, 2015

Who needs water to assemble DNA? Non-aqueous solvent supports DNA nanotechnology May 27th, 2015

One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode -- the ultimate in miniaturization for electronic devices -- with potential for real-world applications May 25th, 2015

Chip Technology

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Technology for Tomorrow’s Market Opportunities and Challenges: LetiDays Grenoble Presents the Possibilities: June 24-25 Event Includes Focus on IoT-Augmented Mobility and Leti’s Latest Results on Silicon Technologies, Sensors, Health Applications and Smart Cities May 27th, 2015

Physicists solve quantum tunneling mystery: ANU media release: An international team of scientists studying ultrafast physics have solved a mystery of quantum mechanics, and found that quantum tunneling is an instantaneous process May 27th, 2015

Discoveries

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Who needs water to assemble DNA? Non-aqueous solvent supports DNA nanotechnology May 27th, 2015

Announcements

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Collaboration could lead to biodegradable computer chips May 28th, 2015

Controlled Release of Anticorrosive Materials in Spot by Nanocarriers May 27th, 2015

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Squeezed quantum cats May 28th, 2015

New chip makes testing for antibiotic-resistant bacteria faster, easier: Researchers at the University of Toronto design diagnostic chip to reduce testing time from days to one hour, allowing doctors to pick the right antibiotic the first time May 28th, 2015

Who needs water to assemble DNA? Non-aqueous solvent supports DNA nanotechnology May 27th, 2015

Controlled Release of Anticorrosive Materials in Spot by Nanocarriers May 27th, 2015

Tools

Seeing the action: UCSB researchers develop a novel device to image the minute forces and actions involved in cell membrane hemifusion May 27th, 2015

Physicists solve quantum tunneling mystery: ANU media release: An international team of scientists studying ultrafast physics have solved a mystery of quantum mechanics, and found that quantum tunneling is an instantaneous process May 27th, 2015

This Slinky lookalike 'hyperlens' helps us see tiny objects: The photonics advancement could improve early cancer detection, nanoelectronics manufacturing and scientists' ability to observe single molecules May 23rd, 2015

Nanometrics Announces Live Webcast of Upcoming Investor and Analyst Day May 20th, 2015

Military

This Slinky lookalike 'hyperlens' helps us see tiny objects: The photonics advancement could improve early cancer detection, nanoelectronics manufacturing and scientists' ability to observe single molecules May 23rd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Nanotherapy effective in mice with multiple myeloma May 21st, 2015

Taking control of light emission: Researchers find a way of tuning light waves by pairing 2 exotic 2-D materials May 20th, 2015

Research partnerships

Collaboration could lead to biodegradable computer chips May 28th, 2015

Supercomputer unlocks secrets of plant cells to pave the way for more resilient crops: IBM partners with University of Melbourne and UQ May 21st, 2015

Taking control of light emission: Researchers find a way of tuning light waves by pairing 2 exotic 2-D materials May 20th, 2015

Organic nanoparticles, more lethal to tumors: Carbon-based nanoparticles could be used to sensitize cancerous tumors to proton radiotherapy and induce more focused destruction of cancer cells, a new study shows May 18th, 2015

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