title: Band-like transport in highly crystalline graphene films from defective graphene oxides.
abstract: The electrical transport property of the reduced graphene oxide (rGO) thin-films synthesized from defective GO through thermal treatment in a reactive ethanol environment at high temperature above 1000 °C shows a band-like transport with small thermal activation energy (Ea~10 meV) that occurs during high carrier mobility (~210 cm(2)/Vs). Electrical and structural analysis using X-ray absorption fine structure, the valence band photo-electron, Raman spectra and transmission electron microscopy indicate that a high temperature process above 1000 °C in the ethanol environment leads to an extraordinary expansion of the conjugated π-electron system in rGO due to the efficient restoration of the graphitic structure. We reveal that Ea decreases with the increasing density of states near the Fermi level due to the expansion of the conjugated π-electron system in the rGO. This means that Ea corresponds to the energy gap between the top of the valence band and the bottom of the conduction band. The origin of the band-like transport can be explained by the carriers, which are more easily excited into the conduction band due to the decreasing energy gap with the expansion of the conjugated π-electron system in the rGO.
authors.affiliation: Department of Applied Physics, Osaka University, Suita 565-0871, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Negishi
authors.affiliation: Center for Nano Materials and Technology, JAIST, Nomi 923-1292, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Akabori
authors.affiliation: Synchrotron Radiation Research Center, Nagoya University, Nagoya 464-8603, Japan.|Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan.|Aichi Synchrotron Research Center, Seto, 489-0965, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.affiliation: Aichi Synchrotron Research Center, Seto, 489-0965, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Department of Applied Physics, Osaka University, Suita 565-0871, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kobayashi