graphene

Graphene passes heat transfer test

grapheneclose-up

Graphene (seen above) offers broad adaptability partly because of its simple make-up: a flat sheet of pure carbon rings in flawless order—just one atom thick. Because of the strong bonding between carbon atoms in the chicken wire-like structure, researchers have documented unprecedented strength, electron mobility, and thermal conductivity in its suspended form, as well as compatibility with thin film silicon transistor devices, making it feasible for low-cost, mass production. (Courtesy: U. Texas)

U. TEXAS (US)—Graphene is one step closer to becoming the ultimate electronic material. A research team reports in the journal Science that graphene still possesses its coveted heat-conducting capability even when supported on a substrate.

This characteristic is crucial as electronic devices become smaller and smaller, presenting engineers with a fundamental problem of keeping the devices cool enough to operate efficiently.

Graphene offers broad adaptability partly because of its simple make-up: a flat sheet of pure carbon rings in flawless order—just one atom thick. Because of the strong bonding between carbon atoms in the chicken wire-like structure, researchers have documented unprecedented strength, electron mobility, and thermal conductivity in its suspended form, as well as compatibility with thin film silicon transistor devices, making it feasible for low-cost, mass production.

A major question has been whether contact with a substrate would compromise its superior properties, exactly because graphene is only one atom thick and thus its properties can be sensitive to interaction with the environment.

Engineers and scientists at the University of Texas at Austin, Boston College, and the France Commission for Atomic Energy detail how graphene still greatly outperforms silicon and copper nanostructures in the latest computer chips for conducting heat even when it is supported on a substrate.

This qualifies graphene as a prime candidate for solving the heat dissipation problems currently limiting development of nanoelectronics. The heat problem is no minor barrier—heat generated per unit area in computer chips are becoming as high as that of a nuclear reactor.

Other researchers have also found that supported graphene still greatly outperforms silicon and copper in terms of electron mobility, a measure of how smoothly an electron can move in a conductor without losing its momentum or energy. Combined with this earlier result, the Shi team’s recent findings suggest that electronic devices made of graphene will potentially generate less heat and conduct heat away from hot spots much more efficiently than devices made of silicon and copper nanostructures.

As such, the devices will consume less energy, be cooler and more reliable, and operate faster than current-generation devices.

The work was supported by the Thermal Transport Processes Program and the Mechanics of Materials Program of the National Science Foundation, the U.S. Office of Naval Research, the U.S. Department of Energy Office of Science, and the University of Texas at Austin.

University of Texas news: www.utexas.edu/news/

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