Chemical vapor deposition of single-wall carbon nanotubes on iron-film-coated sapphire substrates

We report on chemical vapor deposition (CVD) of single-wall carbon nanotubes (SWNTs) on sapphire substrates coated with thin Fe films. The dependence of the SWNTs growth on orientation of the crystallographic face of the sapphire substrate, i.e., defined as A-, R-, and C-faces, was investigated. It was found when the CVD was performed at 800 °C, the largest quantity of SWNTs was produced on the A-face substrate, followed by the R- and C-face substrates. This result implies that the SWNT growth can be controlled by choosing the orientation of the sapphire substrates.