▎ 摘　　要

Millimeter long, vertically oriented, multi-walled carbon nanotube (MWCNT) arrays were pre-aligned and densified using spark plasma sintering (SPS) technique to form aligned MWCNT bulk samples. The combined results of X-ray powder diffraction, Raman spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy show that the MWCNTs largely retain their orientation and individual tubular morphology in the aligned MWCNT bulk samples, and that the SPS process induces inter- and intra-tubular bonding as well as graphene formation. In view of the one-dimensional nature of individual MWCNTs, it is particularly noteworthy that the transverse electrical resistivity rho(T) is slightly lower than the longitudinal resistivity rho(L), whereas the transverse thermal conductivity kappa(T) is similar to 50% Of kappa(L). The room temperature kappa(L) is similar to 31 W/(m K), one of the highest reported in MWCNT bulk samples. In addition, the thermopower measurements show anisotropy and features of phonon drag. (C) 2009 Elsevier Ltd. All rights reserved.