Catalyst Design Using Nanoporous Iron for the Chemical Vapor Deposition Synthesis of Single-Walled Carbon Nanotubes
Figure 5
(a) SEM image of as-grown SWNTs on a silicon wafer using the CVD method incorporating Fe-HMS as catalyst. ((b)–(d)) AFM topographic images of as-grown SWNTs in aqueous NaDDBS solution spin-cast onto an oxidized silicon substrate; color range (height scale) in all AFM images is 10 nm. The images show minimal residual catalyst, small-diameter (3–15 nm) SWNT bundles, and a long (>20 μm) SWNT bundle. The long SWNT bundle is tracked in each image, shown beside the black line as a visual aid. The three markers (triangle, circle, and square) indicate corresponding locations in each image. (e) To determine the diameter of the long SWNT bundle, the height of the bundle was measured at several different positions along the length, yielding an average diameter of 2.0 ± 0.4 nm.
