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Fabrication of highly oriented carbon-nanotube films and its application to an emitter with high efficiency

高取向碳纳米管薄膜的制备及其在高效发射器中的应用

基本信息

批准号：
15560585
负责人：
MATSUMOTO Koichi
金额：
$ 0.9万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560585/
关键词：
carbon nanotube carbon nanotube silicon carbide SiC surface cllipsometry camphor

项目摘要

In order to investigate the initial stage of carbon-nanotube(CNT) formation at the surface decomposition of SiC, we heated the SiC single-crystal substrates (6H-type, C-face polished) in vacuum using an infrared mirror furnace and a turbo-molecular pump, and we analyzed the structure change at the surfaces by means of spectro-ellipsometric measurements.Up to 1100℃, the change in spectra could be interpreted as the decrease of thickness of SiO_2 layer (-4 nm) on the SiC substrate. At 1150℃ and above, however, spectra were distinctly different from those of the samples heated up to 1100℃, and could be interpreted with a three-phase model, in which the surface layer consists of graphite including X% of voids, where the surface layer thickness t=10-50 nm and X=50-70%. This indicates that the surface decomposition of SiC is initiated at this temperature and that the spectro-ellipsometric measurements can detect small changes of optical properties of surface due to the initiation of decomposition.When the substrates were heated for a longer time (80-640 min) at 1300℃, the spectra were essentially different again, and they could be interpreted with a four-phase model, in which the surface layer consists of two graphite layers including different percentages of voids, where the thickness of surface layers t_1=20-50 nm, t_2=20-60 nm and the percentages of voids X=-90%, Y=-50%. This implied that formation of CNT would start at this temperature. This formation was also detected by FE-SEMI observation.Furthermore, we tried to fabricate CNT films by means of H-CVD method using camphor, and found out that carbon nanotubes can be grown using ferrocene as a catalyst.

为了研究SiC表面分解时碳纳米管（CNT）形成的初始阶段，我们加热SiC单晶衬底（6 H型，C面抛光）在真空中用红外反射镜炉和涡轮分子泵加热，并用椭偏光谱法分析了表面结构的变化。光谱的变化可以解释为SiC衬底上SiO_2层厚度的减小（约4 nm）。但在1150℃及以上时，其光谱与加热到1100℃时的光谱明显不同，可以用三相模型解释，即表面层由石墨组成，其中含有X%的空隙，表面层厚度t=10-50 nm，X=50- 70%。这表明在此温度下SiC表面开始分解，并且椭偏光谱测量可以检测到由于分解的开始而引起的表面光学性质的微小变化。（80-640 min）时，光谱又有本质的不同，可以用四相模型解释，其中表面层由两层含有不同空隙率的石墨层组成，其中表面层的厚度t_1=20-50 nm，t_2=20-60 nm，空隙率X=-90%，Y=-50%。这意味着CNT的形成将在该温度下开始。此外，我们还尝试了以樟脑为原料，采用H-CVD法制备碳纳米管薄膜，并发现以二茂铁为催化剂可以生长碳纳米管。