Special Issue Article

Nanoscale Research Letters

, 5:539

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Influence of Ni Catalyst Layer and TiN Diffusion Barrier on Carbon Nanotube Growth Rate

  • Jean-Baptiste A KpetsuAffiliated withPlasmionique Inc Email author 
  • , Pawel JedrzejowskiAffiliated withPlasmionique Inc
  • , Claude CôtéAffiliated withPlasmionique Inc
  • , Andranik SarkissianAffiliated withPlasmionique Inc
  • , Philippe MérelAffiliated withDefence Research & Development Canada—Valcartier
  • , Philips LaouAffiliated withDefence Research & Development Canada—Valcartier
  • , Suzanne ParadisAffiliated withDefence Research & Development Canada—Valcartier
  • , Sylvain DésiletsAffiliated withDefence Research & Development Canada—Valcartier
  • , Hao LiuAffiliated withDepartment of Mechanical and Materials Engineering, University of Western Ontario
    • , Xueliang SunAffiliated withDepartment of Mechanical and Materials Engineering, University of Western Ontario


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°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 SiO2 layer.


Carbon nanotubes Plasma-enhanced chemical vapor deposition Ni catalyst TiN diffusion barrier Scanning electron microscopy