科学家找到培养石墨烯的理想介质

To technology insiders, graphene is a certified¹ big deal. The one-atom thick carbon-based material elicits² rhapsodic（狂热的） descriptions as the strongest, thinnest material known. It also is light, flexible, and able to conduct electricity as well as copper³. Graphene-based electronics promise advances such as faster internet speeds, cheaper solar cells, novel sensors⁴, space suits spun⁵ from graphene yarn⁶, and more. Now a research team at the National Institute of Standards and Technology (NIST) in Boulder⁷, Colo., may help bring graphene's promise closer to reality. While searching for an ideal growth platform for the material, investigators⁸ developed a promising⁹ 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, which is produced by AIP Publishing.

 

The key advance is the grain size of the copper substrate. The large grains are several centimeters in size -- lunkers（同类中特别大的东西） 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 component¹⁰ 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 sapphire¹¹ wafer（晶片） 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 viability¹² of their giant-grained film, the researchers successfully grew graphene grains 0.2 millimeters in diameter on the new copper surface.

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