The optical characterization of 0.4 nm single-walled carbon nanotubes

0.4 nm single-walled carbon nanotubes (SWNTs) of mono size and unique chirality are formed inside micro-channel array of a zeolite single crystal. Before doing the optical measurements on the AFI-nanotubes, Micro-Raman Scattering Spectroscopy is used to characterize the SWNTs in our sample. A fingerprint of SWNTs Raman peak is observed in the high frequency region at about 1600 cm-1. In low frequency region, a diameter dependent of SWNTs Raman peak, the radial breathing mode, is also found at about 540 cm-1, which indicates the diameter of our SWNTs is about 0.41 nm. Temperature dependent Raman shows that the position of the tangential vibration modes is shifted to the right when the temperature decreases. The optical properties of the 0.4 nm SWNTs such as the polarization anisotropy is studied by measuring their transmission spectra in the range from infrared radiation to ultra-violet region by the technique of Fourier Transform Infrared (FTIR) Spectroscopy and UV-VIS Spectroscopy. It is found that the 0.4 nm SWNTs show strong polarization anisotropy from mid-infrared radiation to visible light region. Temperature dependence of the Raman Scattering Spectroscopy and UV-VIS Spectroscopy show that the absorption and transmission through the sample is not temperature dependent. In addition, results are compared to those of lithium-doped and silicon-contained carbon nanotubes. We cannot compare the lithium-doped and the typical carbon nanotubes since the lithium is oxidized after the lithium-doping