| 초록 |
The growth of CNTs at high temperature is easy to achieve micrometer-scale thickness. Furthermore millimeter-scale growth of CNTs so-called as “super growth” has been achieved in many groups recently with a little amount of water-vapor. Water-assisted growth enables to grow CNTs faster in growth rate and less amorphous carbon resulting impurity free. Therefore it is considered that millimeter-scale and impurity less or free CNT could be grown with water-assisted technique. Although there isn’t “super growth” at low temperature yet, we had confirmed these water effect and significantly well-grown in length. We have synthesized multi-walled carbon nanotubes (MWNTs) at low temperature as 450℃ by using simple chemical vapor deposition system. acetylene was adopted to carbon source which is broken easily and catalyst nanoparticles were agglomerated from Invar36(Fe 63wt%, Ni 37wt%) as catalyst layer which have lower melting point than pure Fe or Ni. Water-vapor was evaporated from a canister and carried to the quartz tube by the vacuum without any carrier gas. To investigate the effect of water-vapor, CNTs were grown with or without water-vapor under the same experimental conditions. The result was quite different. The grown MWNTs were characterized by scanning electron microscopy (SEM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM). |
