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

超强磁场中控制反应等离子体的碳纳米管个体生长

基本信息

批准号：
14580511
负责人：
HIRATA Takamichi
金额：
$ 2.3万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14580511/
关键词：
Reactive Plasma Strong Magnetic Field Reactive Plasma Control Carbon Nanotube Individual Growth Ion Bombardment Electric Field of Ion-Sheath Ion Drift Energy

项目摘要

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.

采用等离子体增强化学气相沉积法，在强磁场作用下，直接在射频电极上制备了多壁碳纳米管（MWNTs），通过透射电子显微镜（TEM）分析发现，在B z=0.03 T时，多壁碳纳米管的结构很厚，证实了少量MWNTs相互之间发生了联合收割机结合，形成了较厚的纳米管状石墨材料。在这种情况下，由于离子在rf电极前被负鞘层电压（V_）加速<sh>并以高能量撞击rf电极，因此产生的MWNT被认为是由于高能离子的轰击而变形。当垂直于鞘层电场施加强磁场（B_z=2 T）时，磁场由于离子的磁化而阻止高能离子直接撞击rf电极，即使存在大的鞘层电场。此外，作为碳源的离子朝向rf电极的电流保持足够大以形成纳米管。因此，发现在B_z=2 T下形成的MWNTs被鞘电场良好地取向，并且不会由于朝向rf电极的离子轰击能量的减少而变形。这一结果可以通过离子轰击能量的减少来解释，这是由B_z=2 T时离子的磁化引起的。结果表明，磁场对鞘层电压和离子轰击能量的控制对纳米管的生长有重要影响。