title: Diffusion- and reaction-limited growth of carbon nanotube forests.
abstract: We present a systematic study of the temperature and pressure dependence of the growth rate of vertically aligned small diameter (single- and few-walled) carbon nanotube forests grown by thermal chemical vapor deposition over the temperature range 560-800 degrees C and 10(-5) to 14 mbar partial pressure range, using acetylene as the feedstock and Al(2)O(3)-supported Fe nanoparticles as the catalyst. We observe a pressure dependence of P(0.6) and activation energies of <1 eV. We interpret this as a growth rate limited by carbon diffusion in the catalyst, preceded by a pre-equilibrium of acetylene dissociation on the catalyst surface. The carbon nanotube forest growth was recorded by high-resolution real-time optical imaging.
authors.affiliation: Department of Engineering, University of Cambridge, Cambridge, U.K. ctw31@cam.ac.uk
authors.forename: Christoph Tobias
authors.initials: CT
authors.lastname: Wirth
authors.forename: Can
authors.initials: C
authors.lastname: Zhang
authors.forename: Guofang
authors.initials: G
authors.lastname: Zhong
authors.forename: Stephan
authors.initials: S
authors.lastname: Hofmann
authors.forename: John
authors.initials: J
authors.lastname: Robertson