科研之友
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摘要
We have investigated the temperature and excitation energy dependence of Raman spectra of single-wall carbon nanotubes (SWCNTs). The measured Raman shifts for D and G bands of SWCNTs show a softening behavior upon increasing temperature (83-733 K). A theoretical model is developed to study the frequency shifts for these two Raman modes as a function of temperature; the calculated results agree well with the experimental data. The calculation indicates that the virtual optical-phonon couplings dominate contributions to the temperature variance of frequency shifts for D and G bands of SWCNTs while the pure-volume effect is very weak. Measurements of peak positions and linewidths of D and G bands are also carried out at three different excitation wavelengths ( 325, 514.5 and 785 nm). It is found that not only does the peak position of the D band exhibit a linear increase, but also the linewidth of the G band does upon increasing excitation energy. In addition, we also measure the relative intensity ratios of the D band to the G band (I(D)/I(G)) with temperature and excitation energy in this work.
- 出版日期2007-12-5
- 单位中国科学技术大学
