title: Polymer-sorted semiconducting carbon nanotube networks for high-performance ambipolar field-effect transistors.
abstract: Efficient selection of semiconducting single-walled carbon nanotubes (SWNTs) from as-grown nanotube samples is crucial for their application as printable and flexible semiconductors in field-effect transistors (FETs). In this study, we use atactic poly(9-dodecyl-9-methyl-fluorene) (a-PF-1-12), a polyfluorene derivative with asymmetric side-chains, for the selective dispersion of semiconducting SWNTs with large diameters (>1 nm) from plasma torch-grown SWNTs. Lowering the molecular weight of the dispersing polymer leads to a significant improvement of selectivity. Combining dense semiconducting SWNT networks deposited from an enriched SWNT dispersion with a polymer/metal-oxide hybrid dielectric enables transistors with balanced ambipolar, contact resistance-corrected mobilities of up to 50 cm(2)·V(-1)·s(-1), low ohmic contact resistance, steep subthreshold swings (0.12-0.14 V/dec) and high on/off ratios (10(6)) even for short channel lengths (<10 μm). These FETs operate at low voltages (<3 V) and show almost no current hysteresis. The resulting ambipolar complementary-like inverters exhibit gains up to 61.
authors.affiliation: Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen D-91058, Germany.
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Schiessl
authors.forename: Nils
authors.initials: N
authors.lastname: Fröhlich
authors.forename: Martin
authors.initials: M
authors.lastname: Held
authors.forename: Florentina
authors.initials: F
authors.lastname: Gannott
authors.forename: Manuel
authors.initials: M
authors.lastname: Schweiger
authors.forename: Michael
authors.initials: M
authors.lastname: Forster
authors.forename: Ullrich
authors.initials: U
authors.lastname: Scherf
authors.forename: Jana
authors.initials: J
authors.lastname: Zaumseil
keywords: ambipolar field-effect transistor; inverter; polymer wrapping; selective dispersion; semiconducting single-walled carbon nanotubes