Abrupt self-termination of vertically aligned carbon nanotube growth

Abstract

Real-time height measurements demonstrate that growth of millimeter-high carbon nanotube (CNT) forests terminates abruptly after first exhibiting a steady decay in growth rate. Termination is accompanied by a distinct loss of alignment among the CNTs, which is quantified by small-angle x-ray scattering. Previously suggested diffusion-limited and decay-limited models of kinetics accurately fit the growth period, yet fail to capture the termination behavior and incorrectly predict that growth will continue for much longer durations than observed. It appears that structural disorder is a distinct chemical and/or mechanical signature of self-terminated CNT forest growth.