title: Influence of Ni Catalyst Layer and TiN Diffusion Barrier on Carbon Nanotube Growth Rate.
abstract: Dense, vertically aligned multiwall carbon nanotubes were synthesized on TiN electrode layers for infrared sensing applications. Microwave plasma-enhanced chemical vapor deposition and Ni catalyst were used for the nanotubes synthesis. The resultant nanotubes were characterized by SEM, AFM, and TEM. Since the length of the nanotubes influences sensor characteristics, we study in details the effects of changing Ni and TiN thickness on the physical properties of the nanotubes. In this paper, we report the observation of a threshold Ni thickness of about 4 nm, when the average CNT growth rate switches from an increasing to a decreasing function of increasing Ni thickness, for a process temperature of 700 degrees C. This behavior is likely related to a transition in the growth mode from a predominantly "base growth" to that of a "tip growth." For Ni layer greater than 9 nm the growth rate, as well as the CNT diameter, variations become insignificant. We have also observed that a TiN barrier layer appears to favor the growth of thinner CNTs compared to a SiO(2) layer.
authors.forename: Jean-Baptiste A
authors.initials: JB
authors.lastname: Kpetsu
authors.forename: Pawel
authors.initials: P
authors.lastname: Jedrzejowski
authors.forename: Claude
authors.initials: C
authors.lastname: Côté
authors.forename: Andranik
authors.initials: A
authors.lastname: Sarkissian
authors.forename: Philippe
authors.initials: P
authors.lastname: Mérel
authors.forename: Philips
authors.initials: P
authors.lastname: Laou
authors.forename: Suzanne
authors.initials: S
authors.lastname: Paradis
authors.forename: Sylvain
authors.initials: S
authors.lastname: Désilets
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.forename: Xueliang
authors.initials: X
authors.lastname: Sun