Thin-Film Transistors with Length-Sorted DNA-Wrapped Single-Wall Carbon Nanotubes

Abstract

The present experimental study provides a detailed characterization of the single-wall carbon nanotube (SWNT) length effect on the device characteristics of DNA-wrapped SWNT-network thin-film transistors (TFTs). DNA-assisted dispersion and length separation by high-performance liquid chromatography are used to prepare the SWNTs with average lengths of 400 and 200 nm. The TFTs of both SWNTs exhibit high on/off current ratios of 10⁴−10⁶ and mobilities of 0.4−1.3 cm²/(V s) by optimizing the film density of SWNTs. The optimized density of 200 nm SWNTs is found to be higher than that of 400 nm SWNTs as expected by the percolation theory of two-dimensional random networks, where shorter length SWNTs can maintain high on current despite increasing in the number of SWNT junctions. The present result is an important indicator for realizing high-performance TFTs constructed from SWNTs having desired length.