Influence of oxygen on the growth of carbon nanotubes

The influence of oxygen on the growth of carbon nanotubes (CNTs) using plasma-enhanced chemical vapour deposition has been studied. The cobalt catalyst film and CNTs were characterized by scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscope, x-ray photoelectron spectroscopy and Raman spectroscopy. The results showed that small cobalt oxide particles obtained by O-2-etching were deoxidized back to Co catalyst particles with small size in the CH4/H-2 atmosphere for the growth of CNTs. Small Co particles and the inlet of oxygen in the stage of CNT growth enhanced the yield rate and purity of aligned CNTs.