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Research This is an optical microscope image of a copper film mostly destroyed during graphene growth. What was a continuous copper film has decomposed into grey areas of bare sapphire, rings and irregular patches of copper that appear in a rainbow of colors due to oxidation, and small star-shaped islands of graphene, which appear bright because the graphene protects the copper from oxidation.
Image Credit: David L. Miller, NIST

Published on December 11th, 2013 | by James Ayre

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Graphene Growth Process Improved With Thin Film Of Copper

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December 11th, 2013 by
 
An impressive new means of producing graphene has been created by researchers at the National Institute of Standards and Technology (NIST) in Boulder, Colorado — one that the researchers think will help to bring the commercial production of graphene one step closer to reality.

The new production method utilizes a thin film of copper, one that features massive crystalline grains, as the growth substrate. The primary difference between this method and earlier ones is with regard to the grain size of the copper substrate — the new larger grains (several centimeters in size) can more easily survive the high temperatures needed for graphene growth thanks to their relative size.

This is an optical microscope image of a copper film mostly destroyed during graphene growth. What was a continuous copper film has decomposed into grey areas of bare sapphire, rings and irregular patches of copper that appear in a rainbow of colors due to oxidation, and small star-shaped islands of graphene, which appear bright because the graphene protects the copper from oxidation. Image Credit: David L. Miller, NIST

This is an optical microscope image of a copper film mostly destroyed during graphene growth. What was a continuous copper film has decomposed into grey areas of bare sapphire, rings and irregular patches of copper that appear in a rainbow of colors due to oxidation, and small star-shaped islands of graphene, which appear bright because the graphene protects the copper from oxidation.
Image Credit: David L. Miller, NIST

The inability of most copper films to survive this stage of graphene growth “has been one problem preventing wafer-scale production of graphene devices,” explains NIST researcher Mark Keller.

The American Institute of Physics provides more:

Thin films are an essential component of many electronic, optical, and medical technologies, but the grains in these films are typically smaller than one micrometer. To fabricate the new copper surface, whose grains are about 10,000 times larger, the researchers came up with a two-step process.

First, they deposited copper onto a sapphire wafer held slightly above room temperature. Second, they added the transformative step of annealing, or heat-treating, the film at a much higher temperature, near the melting point of copper. To demonstrate the viability of their giant-grained film, the researchers successfully grew graphene grains 0.2 millimeters in diameter on the new copper surface.

The new findings were just detailed in a paper published in the journal AIP Advances.

Keep up with all the hottest graphene news via our graphene channel.

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.



  • JamesWimberley

    To use graphene sheets as conductive layers in semiconductors, I suppose they need one order of magnitude more: 2mm. As conductive layers in multiple-junction solar cells, three orders of magnitude: 20 cm. Some way to go yet.

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