Turning Graphene 'Gunk' Into the World's Thinnest Glass

Cornell University graduate student Pinshane Huang and Professor David Muller with a model that depicts the atomic structure of glass Photograph by Jason Koski; Courtesy Cornell University

Direct Imaging of a Two-Dimensional Silica Glass on Graphene
Photograph by P.Y. Huang, S. Kurasch et al
The record for the world’s thinnest glass began with scientists noticing some “funny gunk” on a piece of graphene they were growing in a lab. That gunk—”pretty,” as one team member described it—turned out to be a two-atom-wide pane of silica glass, the same stuff in our windows and light bulbs. It had grown purely by accident, the result of an air leak that caused copper foil holding the graphene to react with quartz used in the research.

“This is the way a lot of science works—you’re doing one thing, and then you notice something else,” says David Muller, a professor in the School of Applied & Engineering Physics at Cornell University, whose team worked with researchers at the University of Ulm in Germany. “The most important words in science are, ‘Huh? That’s interesting.’”

The Guinness World Records organization last week selected the glass for inclusion in its 2014 edition, following up on a paper the research team published (pdf) in January 2012 in the journal Nano Letters. It’s just one of the new Guinness records included in the next volume that will feature “Farthest Distance Skateboarded by a Goat” (118 feet by a U.S. goat named Happie) and “Fastest 100m in High Heels” (14.5 seconds by a very brave German woman).

While having no immediate commercial applications, the accidental achievement could one day lead to uses in the batteries of portable electronics and to speedier computer chips. Superthin glass in a lithium ion battery, for example, could help charge the battery faster by shortening the distance ions must travel, Muller said Friday. In computer chips, silicon has been an integral component of semiconductors due to its conducting and insulating properties. Thinner glass inside the switches of a chip could make that chip, and the computer using it, run much faster.

The work also confirmed theories published in 1932 by William Zachariasen, a University of Chicago physicist who later worked on the Manhattan Project. Intrigued by the apparent paradox inherent in glass—it’s a liquid that behaves as a solid—Zachariasen created models of how he believed glass is structured at an atomic level. While crystals have a predictable, ordered structure, glass at its most basic level forms randomly. Images of the silicon and oxygen atoms from the team’s microscope were “exactly” like the 81-year-old model, Muller said.

As part of its work with graphene, Muller said the team is next hoping to “tweak up the chemistry correctly” to produce larger panes of the two-dimensional glass. It is also monitoring the glass for its stability. “Glasses, if you leave them for long enough, they turn into crystals,” Muller said. “But long enough can often mean billions of years. So for an application in any product, we think it’s stable.” Not to mention tiny.

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