Investigation on the effect of nucleation time on CNT growth process using RF-PECVD

Abstract

Carbon Nano Tubes (CNTs) were deposited on Silicon substrate by RF plasma enhanced chemical vapour deposition (RF-PECVD). The deposition was carried out at 550 V bias and 600°C with C2H2 precursor gas diluted with H2 in the ratio of 1:4. Transition metal catalysts are required for CNT growth by PECVD. It is believed that the catalyst on the substrate must be in the form of particles instead of smooth, continuous films. The eventual particle size and the resultant nanotube diameter correlates to film thickness. Thinner films in general lead to smaller particles and tube diameters. While a small grain size is not guaranteed in as-prepared films, steps are taken to break the film into desired particles to form island like structures. This work investigates the effect of Nucleation and the time interval of Nucleation on the CNT growth process.