Growth of Single-Walled Carbon Nanotubes on a Nanorough Surface

Abstract

We compare the growth of single-walled carbon nanotubes (SWNTs) on rough and smooth surfaces. Individual raw HiPco (high-pressure CO) SWNTs are deposited onto porous oxide nanoparticles on a silicon or quartz substrate. The HiPco SWNTs are shown to retain their original catalyst particles that are carbon coated as a result of arrested growth due to bundle formation in the HiPco reactor. Overcoated catalysts are activated with O2 oxidation and SWNTs grown at 900 °C in the presence of CO and H2. The typical length of the SWNTs is more than 10 μm when grown on nanorough surfaces such as fumed silica. This is much longer than the original HiPco SWNTs where the average length is approximately 0.5 μm. They are also much longer than SWNTs grown from the same source material with the same growth conditions on a flat silicon oxide surface. These results support the general impression that extensive interaction of both the nanotube and the catalyst particle with an adjacent surface greatly retards growth.