Semiconductor-enriched single wall carbon nanotube networks applied to field effect transistors

TL;DR

This paper reports the development of high-purity semiconducting single wall carbon nanotube networks for field effect transistors, achieving near-complete metallic nanotube removal and promising electronic performance.

Contribution

It introduces a method using ultracentrifugation and polyfluorene extraction to produce nearly metallic nanotube-free solutions for high-performance FETs.

Findings

Devices show stable p-type behavior in air

On-off ratio of 10^5 achieved

Hole mobility exceeds 2 cm²/Vs

Abstract

Substantial progress on field effect transistors "FETs" consisting of semiconducting single wall carbon nanotubes "s-SWNTs" without detectable traces of metallic nanotubes and impurities is reported. Nearly perfect removal of metallic nanotubes is confirmed by optical absorption, Raman measurements, and electrical measurements. This outstanding result was made possible in particular by ultracentrifugation (150 000 g) of solutions prepared from SWNT powders using polyfluorene as an extracting agent in toluene. Such s-SWNTs processable solutions were applied to realize FET, embodying randomly or preferentially oriented nanotube networks prepared by spin coating or dielectrophoresis. Devices exhibit stable p-type semiconductor behavior in air with very promising characteristics. The on-off current ratio is 10^5, the on-current level is around 10 $\mu$A, and the estimated hole mobility is larger than 2 cm2 / V s.