title: Determination of High-Frequency Dielectric Constant and Surface Potential of Graphene Oxide and Influence of Humidity by Kelvin Probe Force Microscopy.
abstract: We use Kelvin probe force microscopy (KPFM) and capacitance coupling (dC/dz) to study the electrical properties of graphene oxide (GO). We propose using the dC/dz signal to probe the high frequency dielectric constant of mono- and few-layer GO. Our measurements suggest that the dynamic dielectric constant of GO is on the order of εGO ≅ 3.0 ε0, in the high frequency limit, and independent of the number of GO layers. The measurements are performed at a humidity controlled environment (5% of humidity). The effects of increasing humidity on both the dC/dz and KPFM measurements are analyzed.
authors.affiliation: Departmento de Física, Universidade Federal do Ceará , P.O. Box 6030, 60455-900 Fortaleza - Ceará, Brazil.
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Salomão
authors.affiliation: Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais , P.O. 6192, 13083-970 Campinas - São Paulo, Brazil.
authors.forename: Evandro M
authors.initials: EM
authors.lastname: Lanzoni
authors.affiliation: Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais , P.O. 6192, 13083-970 Campinas - São Paulo, Brazil.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Costa
authors.affiliation: Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais , P.O. 6192, 13083-970 Campinas - São Paulo, Brazil.
authors.forename: Christoph
authors.initials: C
authors.lastname: Deneke
authors.affiliation: Departmento de Física, Universidade Federal do Ceará , P.O. Box 6030, 60455-900 Fortaleza - Ceará, Brazil.
authors.forename: Eduardo B
authors.initials: EB
authors.lastname: Barros