title: Wide Band Gap Semiconductor from a Hidden 2D Incommensurate Graphene Phase.
abstract: Producing a usable semiconducting form of graphene has plagued the development of graphene electronics for nearly two decades. Now that new preparation methods have become available, graphene's intrinsic properties can be measured and the search for semiconducting graphene has begun to produce results. This is the case of the first graphene "buffer" layer grown on SiC(0001) presented in this work. We show, contrary to assumptions of the last 40 years, that the buffer graphene layer is not commensurate with SiC. The new modulated structure we've found resolves a long-standing contradiction where ab initio calculations expect a metallic buffer, while experimentally it is found to be a semiconductor. Model calculations using the new incommensurate structure show that the semiconducting π-band character of the buffer comes from partially hybridized graphene incommensurate boundaries surrounding unperturbed graphene islands.
authors.affiliation: The Georgia Institute of Technology , Atlanta, Georgia 30332-0430, United States.
authors.forename: Matthew
authors.identifier: 0000-0002-3010-5634
authors.initials: M
authors.lastname: Conrad
authors.affiliation: The Georgia Institute of Technology , Atlanta, Georgia 30332-0430, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: The Georgia Institute of Technology , Atlanta, Georgia 30332-0430, United States.
authors.forename: Meredith
authors.initials: M
authors.lastname: Nevius
authors.affiliation: University of Wisconsin-Platteville , Platteville, Wisconsin 53818, United States.
authors.forename: Katherine
authors.initials: K
authors.lastname: Jinkins
authors.affiliation: Laboratoire de Physique des Solides, Universit Paris-Sud, CNRS , UMR 8502, F-91405 Orsay Cedex, France.
authors.forename: Arlensiú
authors.initials: A
authors.lastname: Celis
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers , Saint-Aubin, 91192 Gif sur Yvette France.
authors.forename: Maya
authors.initials: M
authors.lastname: Narayanan Nair
authors.affiliation: UR1 CNRS/Synchrotron SOLEIL , Saint-Aubin, 91192 Gif sur Yvette France.
authors.forename: Amina
authors.initials: A
authors.lastname: Taleb-Ibrahimi
authors.affiliation: Laboratoire de Physique des Solides, Universit Paris-Sud, CNRS , UMR 8502, F-91405 Orsay Cedex, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Tejeda
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers , Saint-Aubin, 91192 Gif sur Yvette France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Garreau
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers , Saint-Aubin, 91192 Gif sur Yvette France.
authors.forename: Alina
authors.initials: A
authors.lastname: Vlad
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers , Saint-Aubin, 91192 Gif sur Yvette France.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Coati
authors.affiliation: Department of Physics and Astronomy, University of Missouri-Columbia , Columbia, Missouri 65211, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Miceli
authors.affiliation: The Georgia Institute of Technology , Atlanta, Georgia 30332-0430, United States.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Conrad
keywords: Graphene; SiC; band gap; incommensurate and commensurate phases; surface X-ray diffraction; tight binding