12-02 :: February/March 2012

nanotimes News in Brief The device is immersed in a liquid solvent.

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Experimental design: A sheet of graphene (light blue) is suspended between pillars of silicon dioxide (SiO2

) cap-

ped with a layer of gold (Au) that sit on a layer of SiO2 that was grown thermally on a layer of doped silicon (Si).

An image of a suspended graphene device made by a scanning probe microscope. The graphene sheet is the orange-colored layer suspended between six rectangular columns made of silicon dioxide and capped by gold. © A.K.M. Newaz / Bolotin Lab / Vanderbilt University

When the solvent is electrically biased by a voltage (VG), the charged ions present in the liquid forms an electric double layer (EDL) on both sides of the graphene sheet. © A.K.M Newaz / Bolotin Lab / Vanderbilt University

“The problem is that, when you make graphene, you don’t get just graphene. You also get a lot of other stuff,” said Kirill Bolotin, assistant professor of physics, who conducted the study with research associate A.K.M. Newaz. “Graphene is extraor- dinarily susceptible to external influences so the electrical fields created by charged impurities on its surface scatter the electrons traveling through the graphene sheets, making graphene-based transistors operate slower and heat up more.”

A.K.M. Newaz, Yevgeniy S. Puzyrev, Bin Wang, Sokrates T. Pantelides, Kirill I. Bolotin: Probing charge scattering mechanisms in suspended graphene by varying its die- lectric environment, In: Nature Communications, Vol. 3, March 13, 2012, Article number 734, DOI:10.1038/ ncomms1740:

http://dx.doi.org/10.1038/ncomms1740

Fazel Yavari at Rensselaer Polytechnic Institute has developed a new sensor to detect extremely small quantities of hazardous gases. With his pro- ject, titled “High Sensitivity Detection of Hazardous Gases Using a Graphene Foam Network,” Yavari