A comparative study of cobalt catalyst behavior between silica and quartz substrates for single-walled carbon nanotube growth

Abstract

The cobalt (Co) catalyst behavior for SWNT growth on thermal oxidized silica and single-crystalline quartz by using alcohol chemical vapor deposition (CVD) was compared. The influence of the nature of substrate surface was analyzed from the size and density of both catalyst nanoparticles and SWNTs. The Co nanoparticles, on the quartz substrate after growth, had a mean diameter of about 5.9 nm which was larger than that (2.1 nm) on the silica substrate. Randomly dispersed SWNTs with a higher density were obtained on silica, while aligned SWNTs with a lower density were achieved on ST-cut quartz. The lower density of the nanoparticles on the quartz substrate can be attributed to a larger surface diffusion length of Co atoms in comparison with the silica surface. © 2011 The Surface Science Society of Japan.