| Carbon nanotubes are another gratifying discovery succeeding C60 and C70 in carbon group scientific research, which is of profound significance. Firstly, it is a kind of man-synthesized quasi-one-dimensional quantum wires and facilitates the basic research of low dimensional materials. Not only does it enrich people's perception of this common element in nature, but also it is gradually applied in the fields of nano-electronic device, function materials, fuel cell, etc due to its special structure, mechanics and electrics properties. It can be conjectured that with the perception and application of carbon nanotubes deepening, it will probably have great impact on human being's future. Therefore, carbon nanotubes are regarded as one of the greatest discoveries at the end of twentieth century, and arouses wide attention and interest in all countries'governments, research bodies and industrial commercial world. So far researches in this field have become the front edge and hot spot of material science, condensed matter physics, chemistry.Raman scattering is one of powerful means to investigate carbon nanotubes and plays an important role in understanding their structure and physical meaning. Especially, The strong enhancement of the Raman signal by SERS opens up exciting opportunities for studying the Raman spectrum of a small number of nanotubes, and, maybe, even single nanotube, which provides the information that normal Raman spectrum can not supply to retrieve the intrinsic properties and structures of carbon nanotubes.The paper consists of the following six parts:I . In Part one , the discovery, structure and making method of carbon nanotubes are introduced. Due to its nanosize and unique bonding structure, carbon nanotubes have many outstanding properties which are reflected in the following five aspects: mechanics properties, electrics properties, field emission ,hydrogen storage and electrochemistry properties of carbon nanotubes.II . In Part two, the basic notion, properties of Raman scattering and the parameters involved in Raman scattering are introduced, and the important application of Raman scattering in characterization of material structure is also expounded. The history, enhancement mechanism and application of SERS are recounted as well.III. In part three, the normal Raman and resonant Raman scattering spectra of Single-walled carbon nanotubes are measured at 457.5nm and 632.8nm laser excitation wavelength. By theoretical analysis, the diameter distributions of SWNTs were obtained, style and configuration parameter were speculated furtherly. The components of the tangential stretch mode of SWTNs are assigned, the variational curve of the value of Ig / Id changed with laser power is obtained at 632.8nm excitation, the vibration of D mode is assigned renewedly. In the Raman scattering spectra of SWNTs which was measured using 457.5nm excitation, the new Raman peak at 1421cm'1 is discoveried for the first time.IV. In part four, the results of cryogenic raman spectra investigation show temperature dependence of RBM and GM at low temperature is greatly different from at high temperature, and the intensity of most feature is not reversible at low temperature.V. In part five, the SERRS spectra of SWNTs adsorbed on different metal substrates are studied, Under the normal temperature, the dominant contribution to the enhancement of the Raman single comes from strongly enhanced optical fields in thevicinity of the metallic nanostructures(electromagnetic SERRS enhancement). In general, the SERRS enhancement can also get a contribution from a so-called "chemical" SERS enhancement mechanism, which is based on the specific interaction between the target molecule and the metal substrate.VI . In part six, the purification of SWNTs is discussed and physics-chemistry-connected methods to purify SWNTs are put forward, the surface shapes of SWNTs before and after purification using scanning electron microscopy(SEM) is analyzed and the the purifying effe...
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