Grappling With Graphene

By Brian Fuller

Silicon CMOS is a tough act to follow. The workhorse building block for the world’s electronics has been delivering for system designers for a half century. Despite hand-wringing over its apparent scalability limits, it shows only vague signs of slowing down.

For nearly as many years, it seems, the next great material or alternative to silicon CMOS has popped into the industry’s consciousness promising to be the next big thing - next year. Gallium arsenide, for example, has been next year’s hit technology for four decades.

The latest “it” material, however, could actually deliver on its early hype, and in the process enable the industry not only to continue scaling but to drive deep into previously unexpected depths of low-power design. Graphene - the two-dimensional crystalline form of carbon - first emerged as a term in the late 1980s and gained traction in 2004 when researchers at the University of Manchester extracted graphene layers from graphite - basically using Scotch tape - and then placing on silicon dioxide on a silicon wafer.

This Time It’s Different (Maybe)

The material exhibited fantastic characteristics, including high electron mobility compared to silicon, twice the storage capacity of ultracapacitors, and it was rugged to boot. What’s more, its characteristics apparently remain stable down to the molecular level, unlike other materials used in semiconductor design. The graphene promise is such that in just the past three years, research papers are being written on graphene at the rate of one a day.

“There are two features that make graphene exceptional,” Kirill Bolotin, assistant professor in the Vanderbilt Department of Physics and Astronomy, said in a recent interview. “First, its molecular structure is so resistant to defects that researchers have had to hand-make them to study what effects they have. Second, the electrons that carry electrical charge travel much faster and generally behave as if they have far less mass than they do in ordinary metals or superconductors.”

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