Growth kinetics and microstructure of carbon nanotubes using open air laser chemical vapor deposition

Open air laser-induced chemical vapor deposition (LCVD) was used to rapidly deposit a carbon nanotube forest on a moving substrate prepared with gold–palladium nanoparticles. Butane and propane were used as the carbon source, which was combined with hydrogen gas. Nanotube growth kinetics and alignment characteristics were strongly dependent on laser power density, substrate velocity, catalyst particle size, and the type of precursor mixture used. An increase in the hydrogen concentration improved the purity of the nanotubes by reducing the formation rate of amorphous carbon on the catalytic surface. A multi-stage growth model was proposed.