Experimental and Theoretical Studies of Transport through Large Scale, Partially Aligned Arrays of Single-Walled Carbon Nanotubes in Thin Film Type Transistors

TLDR

The study combines experimental measurements on CVD‑grown, partially aligned SWNT thin‑film transistors with a first‑principles stick‑percolation model to quantitatively describe gate‑modulated transport across varying alignment, coverage, channel length, and orientation. The experiments reveal that even slight SWNT misalignment dramatically degrades transistor performance, indicating that coverage and alignment must be jointly optimized, and that the resulting anisotropic stick‑percolating network produces transport behavior that classical models cannot capture.

Abstract

Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs grown by chemical vapor deposition with systematically varying degrees of alignment and coverage in transistors with a range of channel lengths and orientations perpendicular and parallel to the direction of alignment. A first principles stick-percolation-based transport model provides a simple, yet quantitative framework to interpret the sometimes counterintuitive transport parameters measured in these devices. The results highlight, for example, the dramatic influence of small degrees of SWNT misalignment on transistor performance and imply that coverage and alignment are correlated phenomena and therefore should be simultaneously optimized. The transport characteristics reflect heterogeneity in the underlying anisotropic metal−semiconductor stick-percolating network and cannot be reproduced by classical transport models.