Layer upon layer

CAMBRIDGE, Mass. Graphene, a form of pure carbon arranged in a lattice just one atom thick, has interested countless researchers with its unique strength and its electrical and thermal conductivity. But one key property it lacks - which would make it suitable for a plethora of new uses - is the ability to form a band gap, needed for devices such as transistors, computer chips and solar cells. Now, a team of MIT scientists has found a way to produce graphene in significant quantities in a two- or three-layer form. When the layers are arranged just right, these structures give graphene the much-desired band gap - an energy range that falls between the bands, or energy levels, where electrons can exist in a given material. 'It's a breakthrough in graphene technology,? says Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering at MIT. The new work is described in paper published this week , co-authored by graduate student Chih-Jen Shih, Professor of Chemical Engineering Daniel Blankschtein, Strano and 10 other students and postdocs.