Facile method to control the diameter and density of carbon nanotubes by using a catalyst-embedded supporting layer

Abstract

We have investigated an effective method to control the diameter and the density of carbon nanotubes (CNTs) by introducing a catalyst-embedded supporting layer (CSL) prepared by using rf-magnetron sputtering with a mixed target consisting of Fe and Al2O3. The type of CNTs was changed from single-walled CNTs with a diameter of 0.85 similar to 1.55 nm to multi-walled CNTs with increasing rf-magnetron sputtering power. The controllability of the diameter and the density of the CNTs was confirmed to have been improved by using the rf power during the sputtering of the CSL and the concentration of Fe in the mixed target, respectively.