Effect of morphology of catalyst thin film on carbon nanotube growth

The Ni catalyst films were deposited on single crystal Si by magnetron sputtering system. The surface morphologies of the films were controlled by varying the pretreatment temperature in NH3. We have investigated how the morphology of Ni after thermal treatment influences on the vertically aligned carbon nanotubes growth during thermal chemical vapor deposition. We found that the pretreatment temperature determined the grain size and density of the Ni catalyst that controlled the diameter, length, and density of carbon nanotubes. The degree of crystallization and order of the CNTs as a function of pretreatment temperature was further discussed by Raman spectrums. We found that more aligned and ordered samples correspond to lower ID/IG ratios.