Growth of long aligned carbon nanotubes on amorphous hydrogenated silicon nitride by thermal chemical vapor deposition

Vertically aligned long carbon nanotubes in the range of 80–100 µm have been synthesized on amorphous hydrogenated silicon nitride (a-SiN x :H) coated silicon substrate by thermal chemical vapor deposition of ferrocene and xylene. It is observed that high temperature annealing in oxygen ambient results in formation of crystalline silicon dioxide in the matrix of amorphous silicon nitride due to out diffusion of hydrogen. It is suggested that active sites created on silicon dioxide and a-SiN x :H clusters provide mechanical support for the alignment of long carbon nanotubes. It is proposed that a thin layer of a-SiN x :H prevents silicide formation between the catalyst (Fe) and silicon thus lengthening the catalyst life.