Individual Growth of Carbon Nanotube by Controlling Reactive Plasma in Super-Strong Magnetic Field

点击翻译按钮获取中文摘要

The multi-walled carbon nanotubes (MWNTs) are formed by plasma-enhanced chemical vapor deposition directly on the rf electrode under the condition of the strong magnetic field.It is noted that the nanotube structure at B_z=0.03 T is very thick from the analysis by the transmission electron microscopy (TEM), it is confirmed that a few MWNTs combine with each other and become the thick nanotube-like graphitic material. In this case, since the ions are accelerated by the negative sheath voltage (V_<sh>) in front of the rf electrode and impinge on the rf electrode with high energy, the generated MWNTs are considered to be deformed by the bombardment of the high energy ions.When the strong magnetic field (B_z=2 T) is applied perpendicularly to the sheath electric field, the magnetic field prevents the high energy ions from directly impinging on the rf electrode due to the magnetization of ions, even if the large sheath electric field exists. Furthermore, the current of the ions as a carbon source toward the rf electrode remains to be enough large to form the nanotube. Thus, the MWNTs formed at B_z=2 T are found to be well-aligned by the sheath electric field and not to be deformed due to the reduction of the ion bombardment energy toward the rf electrode.This result can be explained by the reduction of the ion bombardment energy, which is caused by the magnetization of the ions for B_z=2 T. It is found that the controls of the sheath voltage and the ion bombardment energy by the magnetic field introduction have crucial effects on the nanotube growth.