Graphene field-effect devices T. J. Echtermeyer, M. C. Lemme, J. Bolten, M. Baus, M. Ramsteiner and H. Kurz Eur. Phys. J. Special Topics, 148 (2007) 19-26 Published online: 25 September 2007 DOI: 10.1140/epjst/e2007-00222-8