Self-sorted, aligned nanotube networks for thin-film transistors.

To find use in electronics, single-walled carbon nanotubes need to be efficiently separated by electronic type and aligned to ensure optimal and reproducible electronic properties. We report the fabrication of single-walled carbon nanotube (SWNT) network field-effect transistors, deposited from solution, possessing controllable topology and an on/off ratio as high as 900,000. The spin-assisted alignment and density of the SWNTs are tuned by different surfaces that effectively vary the degree of interaction with surface functionalities in the device channel. This leads to a self-sorted SWNT network in which nanotube chirality separation and simultaneous control of density and alignment occur in one step during device fabrication. Micro-Raman experiments corroborate device results as a function of surface chemistry, indicating enrichment of the specific SWNT electronic type absorbed onto the modified dielectric.