Graphene: Hot new material for cooling gadgets?

This graphic shows a graphene layer attached to a metal heat sink and suspended across a trench in the silicon wafer. The graphene was heated up via laser beam to measure its thermal conductivity.

(Credit: Alexander Balandin/University of California at Riverside)

Smaller, faster gadgets may be cool, but keeping them from getting too hot poses challenges.

Consumer electronics, of course, contain many sources of heat, including interconnecting wiring and millions of transistors. In the past, bigger and bigger fans have been employed to keep chips from overheating, thus expanding a gadget's lifespan. But as electronics continue to shrink, so does the space where fans can be placed.

UC Riverside professor Alexander Balandin and graduate student Suchismita Ghosh, who now works at Intel, examine graphene, a material with strong heat-conducting properties.

(Credit: University of California at Riverside)

Enter graphene, a sheet of densely arranged carbon that's just a single atom thick and boasts strong heat-conducting properties. Researchers at UC Riverside's Nano-Device Laboratory have discovered a way to layer the recently discovered material so that it could one day be incorporated into silicon computer chips to make them better at dissipating heat.

The team details its findings in the latest issue of the journal Nature Materials, explaining how multiple layers of graphene, a material with high electron mobility, could essentially serve as heat spreaders in chips, moving the heat around to prevent the formation of damaging hot spots.

Graphene can be be viewed as a plane of carbon atoms extracted from graphite crystals. Researchers from England's University of Manchester first discovered graphene in 2004, and since then have used it to carve nanometer-scale transistors, 1 atom thick and 10 atoms wide, from a single graphene crystal. Earlier this year, IBM announced that it demonstrated a radio-frequency graphene transistor with the highest frequency so far: 100GHz.

"Graphene is one of the hottest materials right now," said Alexander Balandin, a professor of electrical engineering in the Bourns College of Engineering at UC Riverside who led the research group. "Everyone is talking about it."

The practical problem for graphene is the difficulty producing large, high-quality single-atom layers. Balandin's team found that multiple layers of graphene, which are easier to make than the single-layer versions, still retain the material's heat-conducting properties.

Currently, there is no reliable way to synthesize large quantities of graphene, Balandin said. But with progress being made, he added, wider-scale production could be possible in a year or two.