Decelerating Growth of Vertically Aligned Carbon Nanotube Arrays: Kinetic Controlled or Diffusion Controlled?

TL;DR

This paper investigates the growth deceleration mechanisms of vertically aligned carbon nanotube arrays, distinguishing between catalyst decay and diffusion control, and proposes a method to predict maximum CNT forest length.

Contribution

It introduces a non-dimensional modulus to differentiate growth regimes and applies it to predict maximum CNT array length in CVD processes.

Findings

MWNT arrays are typically free of feedstock diffusion limitations

SWNT arrays often face strong diffusion constraints

The method can predict maximum CNT forest length in specific CVD conditions

Abstract

Feedstock and byproduct diffusion in the root growth of aligned CNT arrays was discussed in this work. A non-dimensional modulus was proposed to differentiate catalyst-decay controlled growth deceleration from diffusion controlled one. It was found that aligned MWNT arrays are usually free of feedstock diffusion while SWNT arrays are usually facing strong diffusion limit. The present method can also be utilized to predict the maximum length that CNT forest can grow in certain CVD process.