Growth of Ultrahigh Density Single-Walled Carbon Nanotube Forests by Improved Catalyst Design

Abstract

We have grown vertically aligned single-walled carbon nanotube forests with an area density of 1.5 × 10¹³ cm^–2, the highest yet achieved, by reducing the average diameter of the nanotubes. We use a nanolaminate Fe–Al₂O₃ catalyst design consisting of three layers of Al₂O₃, Fe, and Al₂O₃, in which the lower Al₂O₃ layer is densified by an oxygen plasma treatment to increase its diffusion barrier properties, to allow a thinner catalyst layer to be used. This high nanotube density is desirable for using carbon nanotubes as interconnects in integrated circuits