Macroscopic oriented web of single-wall carbon nanotubes

A macroscopic oriented web (30 cm length) of single-wall carbon nanotubes (SWNTs) with purity higher than 70 at.% has been produced by dc arc discharge evaporation of a carbon electrode including 1 at.% Fe catalyst in H2–Ar mixture gas. The SWNTs possess high crystallinity and a ‘clean’ surface. Moreover, the coexisting Fe catalyst nanoparticles can be completely eliminated by a two-step purification process (heating in air at 693 K and mild hydrochloric acid treatment). This study provides a simple, inexpensive and efficient method for producing high-quality SWNTs on a large scale, and enables us to investigate the physical properties of SWNTs in bulk.