While searching for an ideal growth platform for the material, investigators from National Institute of Standards and Technology (NIST) in Boulder, Colorado, developed a promising new recipe for a graphene substrate: a thin film of copper with massive crystalline grains.
NIST researcher Mark Keller said that the key advance is the grain size of the copper substrate, asserting that 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.
He said that the inability of most copper films to survive this stage of graphene growth has been one problem preventing wafer-scale production of graphene devices.
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.
The study has been published in the journal AIP Advances.
--ANI (Posted on 09-12-2013)