Study on Terahertz Spectra of Multi-Walled Carbon Nanotubes
SU Tong-fu1, YU Bin2, HAN Peng-yu3, LI Yong-liang4, LI Wei1, ZHAO Guo-zhong2, GONG Chang-rong5*
1. Department of Chemistry, Henan Agricultural University, Zhengzhou 450002, China 2. Department of Physics, Capital Normal University, Beijing 100037, China 3. Center for THz Research, Rensselaer Polytechnic Institute, Troy 12180, USA 4. Analytical and Testing Center，Beijing Normal University，Beijing 100875, China 5. College of Tobacco, Henan Agricultural University, Zhengzhou 450002，China
Abstract：In the present paper, the authors report the characterization of multiwalled carbon nanotube at terahertz (THz) frequency range using terahertz time-domain spectroscopy. The surface appearances and microanalysis of multiwalled carbon nanotubes were measured by scanning electron microscope in order to fully understand the unique features and applications of multiwalled carbon nanotube. The results show that the refractive indexes of the sample decrease with increasing frequency in the frequency range of 0.2 to 2 THz, while the absorption coefficients of the sample increase with increasing frequency. In addition, the curve of terahertz absorption coefficients can be fitted by a straight line with a slope of 1.92. From the results of scanning electron microscope, the ranges of inner diameter and outer diameters of the sample were from 5 to 15 nm and from 15 to 25 nm, respectively, and its length was in the order of micrometer. The results of microanalysis of its elemental composition showed that the content of element C was about 94% and the rest were O and Cl elements, which were impurity elements. Mathematical modes of terahertz absorption and refractive indexes in the frequency range of 0.2 to 2.0 THz were established after taking into account Taylor expansion and Maxwell’s equations, and the calculation was in relatively good agreement with the observed values of the sample in general. The terahertz refractive indexes and absorption properties of multiwalled carbon nanotube were mainly attributed to the chemical compositions and molecular weight, and carbon nanotubes with different content of carbon could show different terahertz absorption spectra and disclose different unique functions.
Key words：Terahertz spectra;Multi-walled carbon nanotubes;Scanning electron microscope (SEM);X-ray microanalysis
苏同福1，于 斌2，韩鹏昱3，李永良4，李 伟1，赵国忠2，宫长荣5* . 多壁碳纳米管太赫兹图谱研究[J]. 光谱学与光谱分析, 2009, 29(11): 3154-3157.
SU Tong-fu1, YU Bin2, HAN Peng-yu3, LI Yong-liang4, LI Wei1, ZHAO Guo-zhong2, GONG Chang-rong5* . Study on Terahertz Spectra of Multi-Walled Carbon Nanotubes. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2009, 29(11): 3154-3157.
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