Semi-quantitative study on the fabrication of densely packed and vertically aligned single-walled carbon nanotubes

This paper presents, for the first time, a semi-quantitative study on the production of densely packed and vertically aligned (DPVA) single-walled carbon nanotubes (SWNTs) from ultra-thin catalytic films. An up-to-date highest volume density (60-70 kg m^-3) and the corresponding high surface density on the order of 10¹⁶ m^-2 of DPVA-SWNTs have been achieved by point-arc microwave plasma chemical vapor deposition. The precise thickness control of the sandwich-like catalytic nanostructure of 0.5 nm Al₂O₃/0.5 nm Fe/>5 nm Al₂O₃, developed by the authors, and a short-time (5 min) heat pretreatment of substrates at a temperature as low as 600 °C play the very key role in the process of fabricating DPVA-SWNTs.