Huge grains of copper promote better graphene growth

Dec 06, 2013
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. Credit: David L. Miller, NIST

To technology insiders, graphene is a certified big deal. The one-atom thick carbon-based material elicits rhapsodic descriptions as the strongest, thinnest material known. It also is light, flexible, and able to conduct electricity as well as copper. Graphene-based electronics promise advances such as faster internet speeds, cheaper solar cells, novel sensors, space suits spun from graphene yarn, and more.

Now a research team at the National Institute of Standards and Technology (NIST) in Boulder, Colo., may help bring 's promise closer to reality. While searching for an ideal growth platform for the material, investigators developed a promising new recipe for a graphene substrate: a thin film of copper with massive crystalline grains. The team's findings appear in the journal AIP Advances.

The key advance is the grain size of the copper substrate. The large grains are several centimeters in size – lunkers by microelectronics standards – but their relative bulk enables them to survive the high temperatures needed for graphene growth, explained NIST researcher Mark Keller.

The inability of most copper films to survive this stage of graphene growth "has been one problem preventing wafer-scale production of graphene devices," Keller said.

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 . To demonstrate the viability of their giant-grained film, the researchers successfully grew graphene 0.2 millimeters in diameter on the new .

Explore further: New 'designer carbon' boosts battery performance

More information: The article, "Giant secondary grain growth in Cu films on sapphire" by David L. Miller, Mark W. Keller, Justin M. Shaw, Katherine P. Rice, Robert R. Keller and Kyle M. Diederichsen appears in the journal AIP Advances: dx.doi.org/10.1063/1.4817829

Related Stories

Researchers grow graphene on silver

Nov 18, 2013

(Phys.org) —Graphene, a one-atom-thick carbon layer with extraordinary conductivity and strength, holds promise for a range of applications, but to realize its potential scientists must perfect techniques to tune its properties. ...

Hydrogen may be key to growth of high-quality graphene

Jul 18, 2011

A new approach to growing graphene greatly reduces problems that have plagued researchers in the past and clears a path to the crystalline form of graphite's use in sophisticated electronic devices of tomorrow.

Recommended for you

New 'designer carbon' boosts battery performance

9 hours ago

Stanford University scientists have created a new carbon material that significantly boosts the performance of energy-storage technologies. Their results are featured on the cover of the journal ACS Central Sc ...

Graphene and diamonds prove a slippery combination

May 25, 2015

Scientists at the U.S. Department of Energy's Argonne National Laboratory have found a way to use tiny diamonds and graphene to give friction the slip, creating a new material combination that demonstrates ...

Artificial muscles get graphene boost

May 22, 2015

Researchers in South Korea have developed an electrode consisting of a single-atom-thick layer of carbon to help make more durable artificial muscles.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.