Laser ablation for the synthesis of carbon nanotubes

Abstract

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cmat a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of 'side pumped', preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.