Analysis of catalytic growth of carbon nanotubes by ACCVD method

This article describes the influence of a co-catalyst interlayer and various diffusion barriers on growth of Carbon Nanotubes (CNTs) by Alcohol Catalytic Chemical Vapour Deposition (ACCVD) method. Silicon wafers covered with thermal oxide or polycrystalline diamond film were used as substrates. The catalyst was Ni thin film and the co-catalyst interlayer between the substrate and Ni catalyst film was one of the following metals: Al, Cu and Ti. All catalyst films, including metal interlayers, were deposited by Pulsed Laser Deposition Technique (PLD). Comparison of the various types of the co-catalysts (Al, Cu, Ti) leads to the conclusion that Cu co-catalyst is suitable for producing very thin single wall carbon nanotubes (SWCNTs) whereas the combination of Al and Ni provides a good condition to the catalytic growth of CNTs. In addition, we observed also the influence of various diffusion barriers on growth of CNTs. One of the prepared samples had polycrystalline diamond layer instead of thermal oxide serving as diffusion barrier between Si substrate and catalyst. We can conclude that polycrystalline diamond thin film has good impact to the growth conditions. We also investigated the influence of surface roughness on growth of CNTs. Prepared samples were analysed by Raman Spectroscopy and Scanning Electron Microscopy (SEM).