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Substrate‐Wide Confined Shear Alignment of Carbon Nanotubes for Thin Film Transistors
Author(s) -
Jinkins Katherine R.,
Chan Jason,
Jacobberger Robert M.,
Berson Arganthaël,
Arnold Michael S.
Publication year - 2019
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201800593
Subject(s) - materials science , carbon nanotube , transistor , optoelectronics , wafer , nanotechnology , substrate (aquarium) , flexible electronics , carbon nanotube field effect transistor , thin film transistor , nanotube , field effect transistor , layer (electronics) , voltage , electrical engineering , oceanography , geology , engineering
To exploit their charge transport properties in transistors, semiconducting carbon nanotubes must be assembled into aligned arrays comprised of individualized nanotubes at optimal packing densities. However, achieving this control on the wafer‐scale is challenging. Here, solution‐based shear in substrate‐wide, confined channels is investigated to deposit continuous films of well‐aligned, individualized, semiconducting nanotubes. Polymer‐wrapped nanotubes in organic ink are forced through sub‐mm tall channels, generating shear up to 10 000 s −1 uniformly aligning nanotubes across substrates. The ink volume and concentration, channel height, and shear rate dependencies are elucidated. Optimized conditions enable alignment within a ±32° window, at 50 nanotubes µm −1 , on 10 × 10 cm 2 substrates. Transistors (channel length of 1–5 µm) are fabricated parallel and perpendicular to the alignment. The parallel transistors perform with 7× faster charge carrier mobility (101 and 49 cm 2 V −1 s −1 assuming array and parallel‐plate capacitances, respectively) with high on/off ratio of 10 5 . The spatial uniformity varies ±10% in density, ±2° in alignment, and ±7% in mobility. Deposition occurs within seconds per wafer, and further substrate scaling is viable. Compared to random networks, aligned nanotube films promise to be a superior platform for applications including sensors, flexible/stretchable electronics, and light emitting and harvesting devices.