Nanotechnology Now







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

News and information

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

Graphene

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

Imaging

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Govt.-Legislation/Regulation/Funding/Policy

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

New nanodevice defeats drug resistance: Tiny particles embedded in gel can turn off drug-resistance genes, then release cancer drugs March 2nd, 2015

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Chip Technology

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

onic Present breakthrough in CMOS-based Transceivers for mm-Wave Radar Systems March 1st, 2015

Discoveries

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

Colon + septic tank = unique, at times stinky, study: Researchers use lab-scale human colon and septic tank to study impact of copper nanoparticles on the environment March 2nd, 2015

Materials/Metamaterials

Breakthrough in OLED technology March 2nd, 2015

Moving molecule writes letters: Caging of molecules allows investigation of equilibrium thermodynamics February 27th, 2015

Graphene shows potential as novel anti-cancer therapeutic strategy: University of Manchester scientists have used graphene to target and neutralise cancer stem cells while not harming other cells February 26th, 2015

Learning by eye: Silicon micro-funnels increase the efficiency of solar cells February 25th, 2015

Announcements

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Tools

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Mass spectrometers with optimised hydrogen pumping March 1st, 2015

Military

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Simulating superconducting materials with ultracold atoms: Rice physicists build superconductor analog, observe antiferromagnetic order February 23rd, 2015

New nanogel for drug delivery: Self-healing gel can be injected into the body and act as a long-term drug depot February 19th, 2015

Printing/Lithography/Inkjet/Inks

Maximum Precision in 3D Printing: New complete solution makes additive manufacturing standard for microfabrication February 26th, 2015

SUNY Poly CNSE Researchers and Corporate Partners to Present Forty Papers at Globally Recognized Lithography Conference: SUNY Poly CNSE Research Group Awarded Both ‘Best Research Paper’ and ‘Best Research Poster’ at SPIE Advanced Lithography 2015 forum February 25th, 2015

World’s first compact rotary 3D printer-cum-scanner unveiled at AAAS by NTU Singapore start-up: With production funded by crowdsourcing, the first unit will be delivered to the United States in March February 16th, 2015

3-D printing with custom molecules creates low-cost mechanical sensor February 10th, 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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE