Synthesis of carbon nanotubes on silicon nanowires by thermal chemical vapor deposition

Carbon nanotubes (CNTs) were grown on a silicon nanowire substrate with Ni-catalyst layers of different thicknesses using thermal chemical vapor deposition. Scanning electron microscopy was used to observe the surface morphology, and Raman spectroscopy was used to investigate the structural changes in relation to the thicknesses of the catalyst deposited on the substrate. Field-emission characteristics of CNTs were also correlated with the catalyst thicknesses. The catalyst thickness was found to effectively change the field-emission characteristics of the CNTs. Obvious changes in the diameters, population density, and morphology of CNTs were found with differences in catalyst thickness. The field-emission characteristics of CNTs were dependent on their diameter.