HOUSTON -- (Nov. 11, 2010) -- Future computers may run a little sweeter, thanks to a refinement in the manufacture of graphene at Rice University.
Rice researchers have learned to make pristine sheets of graphene, the one-atom-thick form of carbon, from plain table sugar and other carbon-based substances. They do so in a one-step process at temperatures low enough to make graphene easy to manufacture.
The lab of Rice chemist James Tour reported in the online version of the journal Nature this week that large-area, high-quality graphene can be grown from a number of carbon sources at temperatures as low as 800 degrees Celsius (1,472 F). As hot as that may seem, the difference between running a furnace at 800 and 1,000 degrees Celsius is significant, Tour said.
"At 800 degrees, the underlying silicon remains active for electronics, whereas at 1,000 degrees, it loses its critical dopants," said Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science.
Zhengzong Sun, a fourth-year graduate student in Tour's lab and primary author of the paper, found that depositing carbon-rich sources on copper and nickel substrates produced graphene in any form he desired: single-, bi- or multilayer sheets that could be highly useful in a number of applications.
Sun and his colleagues also found the process adapts easily to producing doped graphene; this allows the manipulation of the material's electronic and optical properties, which is important for making switching and logic devices.
For pristine graphene, Sun started with a thin film of poly (methyl methacrylate) (PMMA) -- perhaps best known in its commercial guise as Plexiglas -- spun onto a copper substrate that acted as a catalyst. Under heat and low pressure, flowing hydrogen and argon gas over the PMMA for 10 minutes reduced it to pure carbon and turned the film i
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