Friday, July 8, 2011

Wrinkles Rankle Graphene

Using scanning transmission X-ray microscopy and near edge X-ray absorption fine structure (NEXAFS) spectroscopy, a team of researchers led by the University at Buffalo (part of the State University of New York) have found that folds and ripples in a graphene sheet and/or chance contaminants from processing—possibly hiding in those wrinkles—disrupt and slow electron flow across the sheet, impairing its conductive properties. This means simple processing flaws can seriously degrade graphene, according to a study published June 28 in Nature Communications. (Scientific American is part of Nature Publishing Group.) Under ideal conditions, an electron "cloud" lines the surface of graphene samples that enables the high-speed transit of electrons. Wrinkles and imperfections in these samples, however, distort the cloud and create bottlenecks, according to the team, which also included scientists from the National Institute of Standards and Technology (NIST), the Molecular Foundry at Lawrence Berkeley National Laboratory and the SEMATECH research consortium. More>