title: On-Chip Chemical Self-Assembly of Semiconducting Single-Walled Carbon Nanotubes (SWNTs): Toward Robust and Scale Invariant SWNTs Transistors.
abstract: In this paper, the fabrication of carbon nanotubes field effect transistors by chemical self-assembly of semiconducting single walled carbon nanotubes (s-SWNTs) on prepatterned substrates is demonstrated. Polyfluorenes derivatives have been demonstrated to be effective in selecting s-SWNTs from raw mixtures. In this work the authors functionalized the polymer with side chains containing thiols, to obtain chemical self-assembly of the selected s-SWNTs on substrates with prepatterned gold electrodes. The authors show that the full side functionalization of the conjugated polymer with thiol groups partially disrupts the s-SWNTs selection, with the presence of metallic tubes in the dispersion. However, the authors determine that the selectivity can be recovered either by tuning the number of thiol groups in the polymer, or by modulating the polymer/SWNTs proportions. As demonstrated by optical and electrical measurements, the polymer containing 2.5% of thiol groups gives the best s-SWNT purity. Field-effect transistors with various channel lengths, using networks of SWNTs and individual tubes, are fabricated by direct chemical self-assembly of the SWNTs/thiolated-polyfluorenes on substrates with lithographically defined electrodes. The network devices show superior performance (mobility up to 24 cm2V-1s-1), while SWNTs devices based on individual tubes show an unprecedented (100%) yield for working devices. Importantly, the SWNTs assembled by mean of the thiol groups are stably anchored to the substrate and are resistant to external perturbation as sonication in organic solvents.
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747, AG, The Netherlands.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Derenskyi
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747, AG, The Netherlands.
authors.forename: Widianta
authors.initials: W
authors.lastname: Gomulya
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747, AG, The Netherlands.
authors.forename: Wytse
authors.initials: W
authors.lastname: Talsma
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747, AG, The Netherlands.
authors.forename: Jorge Mario
authors.initials: JM
authors.lastname: Salazar-Rios
authors.affiliation: Chemistry Department and Institute for Polymer Technology, Wuppertal University, Gauss-Str. 20, D-42119, Wuppertal, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Fritsch
authors.affiliation: IBM Research - Zürich, Säumerstrasse 4, CH-8803, Rüschlikon, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Nirmalraj
authors.affiliation: IBM Research - Zürich, Säumerstrasse 4, CH-8803, Rüschlikon, Switzerland.
authors.forename: Heike
authors.initials: H
authors.lastname: Riel
authors.affiliation: Chemistry Department and Institute for Polymer Technology, Wuppertal University, Gauss-Str. 20, D-42119, Wuppertal, Germany.
authors.forename: Sybille
authors.initials: S
authors.lastname: Allard
authors.affiliation: Chemistry Department and Institute for Polymer Technology, Wuppertal University, Gauss-Str. 20, D-42119, Wuppertal, Germany.
authors.forename: Ullrich
authors.initials: U
authors.lastname: Scherf
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747, AG, The Netherlands.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Loi
keywords: carbon nanotubes; field-effect transistors; polymer-wrapping; self-assembly