Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Tighter 'stitching' means better graphene, say scientists

Muller lab
False-color microscopy images show examples of graphene grown slowly, resulting in large patches with poor stitching, and graphene grown more quickly, resulting in smaller patches with tighter stitching and better performance.
Muller lab

False-color microscopy images show examples of graphene grown slowly, resulting in large patches with poor stitching, and graphene grown more quickly, resulting in smaller patches with tighter stitching and better performance.

Abstract:
Similar to how tighter stiches make for a better quality quilt, the "stitching" between individual crystals of graphene affects how well these carbon monolayers conduct electricity and retain their strength, Cornell researchers report.

Tighter 'stitching' means better graphene, say scientists

Ithaca, NY | Posted on June 4th, 2012

The quality of this "stitching" -- the boundaries at which graphene crystals grow together and form sheets -- is just as important as the size of the crystals themselves, which scientists had previously thought held the key to making better graphene.

The researchers, led by Jiwoong Park, assistant professor of chemistry and chemical biology and a member of the Kavli Institute at Cornell for Nanoscale Science, used advanced measurement and imaging techniques to make these claims, detailed online in the journal Science June 1.

Graphene is a single layer of carbon atoms, and materials scientists are engaged in a sort of arms race to manipulate and enhance its amazing properties -- tensile strength, high electrical conductance, and potential applications in photonics, photovoltaics and electronics. Cartoons depict graphene like a perfect atomic chicken wire stretching ad infinitum.

In reality, graphene is polycrystalline; it is grown via a process called chemical vapor deposition, in which small crystals, or grains, at random orientations grow by themselves and eventually join together in carbon-carbon bonds.

In earlier work published in Nature last January, the Cornell group had used electron microscopy to liken these graphene sheets to patchwork quilts -- each "patch" represented by the orientation of the graphene grains (and false colored to make them pretty).

They, along with other scientists, wondered how graphene's electrical properties would hold up based on its polycrystalline nature. Conventional wisdom and some prior indirect measurements had led scientists to surmise that growing graphene with larger crystals -- fewer patches -- might improve its properties.

The new work questions that dogma. The group compared how graphene performed based on different rates of growth via chemical vapor deposition; some they grew more slowly, and others, very quickly. They found that the more reactive, quick-growth graphene, with more patches, in certain ways performed better electronically than the slower growth graphene with larger patches.

As it turned out, faster growth led to tighter stitching between grains, which improved the graphene's performance, as opposed to larger grains that were more loosely held together.

"What's important here is that we need to promote the growth environment so that the grains stitch together well," Park said. "What we are showing is that grain boundaries were a main concern, but it could be that it doesn't matter. We are finding that it's probably OK."

Equal in importance to these observations were the complex techniques they used to make the measurements -- no easy task. A four-step electron beam lithography process, developed by Adam Tsen, an applied physics graduate student and the paper's first author, allowed the researchers to place electrodes on graphene, directly on top of a 10 nanometer-thick membrane substrate to measure electrical properties of single grain boundaries.

"Our technique sets a tone for how we can measure atomically thin materials in the future," Park added.

Collaborators led by David A. Muller, professor of applied and engineering physics and co-director of the Kavli Institute at Cornell for Nanoscale Science, used advanced transmission electron microscopy techniques to help Park's group image their graphene to show the differences in the grain sizes.

The work was supported by the Air Force Office of Scientific Research, and the National Science Foundation through the Cornell Center for Materials Research. Fabrication was performed at the Cornell NanoScale Science and Technology Facility.

####

For more information, please click here

Contacts:
Media Contact:
John Carberry
(607) 255-5353


Cornell Chronicle:
Anne Ju
(607) 255-9735

Copyright © Cornell University

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

Imaging

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

News and information

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Graphene/ Graphite

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

Graphene is strong, but is it tough? Berkeley Lab scientists find that polycrystalline graphene is not very resistant to fracture February 7th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Chip Technology

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Scientists guide gold nanoparticles to form 'diamond' superlattices: DNA scaffolds cage and coax nanoparticles into position to form crystalline arrangements that mimic the atomic structure of diamond February 4th, 2016

Discoveries

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Materials/Metamaterials

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Graphene is strong, but is it tough? Berkeley Lab scientists find that polycrystalline graphene is not very resistant to fracture February 7th, 2016

Scientists take key step toward custom-made nanoscale chemical factories: Berkeley Lab researchers part of team that creates new function in tiny protein shell structures February 6th, 2016

Discovery of the specific properties of graphite-based carbon materials February 6th, 2016

Announcements

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

Tools

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Researchers discover new phase of boron nitride and a new way to create pure c-BN February 5th, 2016

Cornell researchers create first self-assembled superconductor February 1st, 2016

New record in nanoelectronics at ultralow temperatures January 28th, 2016

Military

Scientists guide gold nanoparticles to form 'diamond' superlattices: DNA scaffolds cage and coax nanoparticles into position to form crystalline arrangements that mimic the atomic structure of diamond February 4th, 2016

Researchers develop completely new kind of polymer: Hybrid polymers could lead to new concepts in self-repairing materials, drug delivery and artificial muscles January 30th, 2016

Nano-coating makes coaxial cables lighter: Rice University scientists replace metal with carbon nanotubes for aerospace use January 28th, 2016

Scientists build a neural network using plastic memristors: A group of Russian and Italian scientists have created a neural network based on polymeric memristors -- devices that can potentially be used to build fundamentally new computers January 28th, 2016

Printing/Lithography/Inkjet/Inks

Teijin to Participate in Nano Tech 2016 January 21st, 2016

New bimetallic alloy nanoparticles for printed electronic circuits: Production of oxidation-resistant copper alloy nanoparticles by electrical explosion of wire for printed electronics January 5th, 2016

Photonic “sintering” may create new solar, electronics manufacturing technologies December 1st, 2015

Screen Printable Functionalised Graphene Ink November 3rd, 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







Car Brands
Buy website traffic