Influence of the nano-structure and composition of titanium nitride based substrate on the carbon nanotubes grown by CVD

Abstract

We present a study of the influence of the substrate nano-structure and composition on the morphological properties of the carbon nanotubes (CNTs) by sequentially growing in situ TiNx:Oy film, dispersed nickel catalyst particles, and CNTs obtained by CVD. The results show that the stoichiometry and the nanostructures of the substrate intervene in the growing process. Particular attention is pay to the influence of oxygen on the CNT growths. The results show that O prevents the coarsening of the catalyst nickel particles, avoiding the surface diffusion mobility of the precursor atoms involved in the nanotubes growth (Ostwald ripening)1. The dependence of the size and density of the CNTs on the amount of O present in the substrate are reported and discussed. The experimental findings show that, besides acting as diffusion barrier between the catalyst particles and the silicon, the substrate also influences the kinetics of growth of carbon nanotubes.