Optical and electrical properties of preferentially anisotropic single-walled carbon-nanotube films in terahertz region

The absorption and dispersion of the aligned single walled carbon nanotubes (SWNT) film from 0.2 to 2.0 THz were measured without invoking the Kramers-Kronig relationship. The real conductivity was found to increase with increasing frequencies. The measured conductivity was fitted by employing the Maxwell-Garnet (M-G) model combined with the drude-Lorentz model to explain the carbon nanotube network in an effective air medium. The results show that a significant portion of the conductivity is contributed from the localized states or phonon scattering from the doped semiconducting nanotubes.