title: Coulomb Blockade in a Two-Dimensional Conductive Polymer Monolayer.
abstract: Electronic transport was investigated in poly(3-hexylthiophene-2,5-diyl) monolayers. At low temperatures, nonlinear behavior was observed in the current-voltage characteristics, and a nonzero threshold voltage appeared that increased with decreasing temperature. The current-voltage characteristics could be best fitted using a power law. These results suggest that the nonlinear conductivity can be explained using a Coulomb blockade (CB) mechanism. A model is proposed in which an isotropic extended charge state exists, as predicted by quantum calculations, and percolative charge transport occurs within an array of small conductive islands. Using quantitatively evaluated capacitance values for the islands, this model was found to be capable of explaining the observed experimental data. It is, therefore, suggested that percolative charge transport based on the CB effect is a significant factor giving rise to nonlinear conductivity in organic materials.
authors.affiliation: Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Akai-Kasaya
authors.affiliation: Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Okuaki
authors.affiliation: Nagoya University Venture Business Laboratory, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nagano
authors.affiliation: Japan Advanced Institute of Sciene and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mitani
authors.affiliation: Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwahara