Growth of diameter-controlled carbon nanotubes using monodisperse nickel nanoparticles obtained with a differential mobility analyzer

Diameter-controlled multiwalled carbon nanotubes (MWNTs) have been grown by hot-filament chemical vapor deposition using nickel nanoparticles as catalyst. The nanoparticles were generated by laser ablation, classified with a differential mobility analyzer, and deposited onto silicon substrate. The particle size is tunable down to 2–3 nm, and particles with a geometric mean diameter of 5.1 nm (geometric standard deviation: 1.1) were used for carbon-nanotube growth. MWNTs were grown on the substrate using acetylene at 550 °C. The particles did not coalesce during growth, and the MWNTs had outer diameters matching the particle sizes, indicating that the current method can produce diameter-controlled MWNTs.