Probing the inter-tube transport in aligned and random multiwall carbon nanotubes

Abstract

The temperature and magnetic field dependence of conductivity has been used to probe the inter-tube transport in multiwall carbon nanotubes (MWNTs). The scanning electron microscopy images show highly aligned and random distribution of MWNTs. The conductivity in aligned carbon nanotube (ACNT) and random carbon nanotube (RCNT) samples at low temperature follows T1/2 (at T < 8 K) and T3/4 (at T > 8 K) dependence in accordance with the weak localization and electron-electron (e-e) interaction model. The values of diffusion coefficient in ACNT and RCNT are 0.25 × 10−2 and 0.71 × 10−2 cm2 s−1, respectively, indicating that larger number of inter-tube junctions in later enhances the bulk transport. The positive magnetoconductance (MC) data in both samples show that the weak localization contribution is dominant. However, the saturation of MC at higher fields and lower temperatures indicate that e-e interaction is quite significant in RCNT. The T−3/4 and T−1/2 dependence of inelastic scattering length (lin) in ACNT and RCNT samples show that the inelastic e-e scattering is more important in aligned tubes.