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.