AVS 51st International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThA

Invited Paper AS-ThA6
The Structure and Growth of Single- and Double-Walled Carbon Nanotubes

Thursday, November 18, 2004, 3:40 pm, Room 210A

Session: Fuel Cell, Catalytic, and Nanomaterials Characterization
Presenter: J.-M. Zuo, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
Single- and double-walled carbon nanotubes have potential applications for future electronics and nanomachines. However, as-grown carbon nanotubes have a dispersion of structures, which differ in both diameter and chirality, and electric and mechanical properties. Characterization of these nanotubes has been a challenge. Recently, we developed a coherent electron diffraction/imaging technique by forming a nanometer-sized parallel beam of electrons that can be used to record diffraction patterns from individual nanotubes. Furthermore, the combination of coherence and high angular resolution allows the over-sampling of diffraction pattern and solution of phase problem by ab initio phase retrieval, thus, imaging of carbon nanotubes. Using this technique, we have investigated a large number of single- and double-walled carbon nanotubes. We found that neither zig-zag nor arm-chair tubes is preferred for growth. Double-walled carbon nanotubes are generally incommensurate and there is a peaked distribution of spacings between two tubes. The implication of these findings will be discussed based on the growth mechanism of carbon nanotubes. The technique of coherent electron nanodiffraction and diffractive imaging by the solution of the phase problem is general and applicable to other nanostructures. @FootnoteText@ *In collaboration with J. Tao, J. Bording, Boquan Li, M. Gao, L. Nagahara, R. Zhang, R. Twesten and I. Petrov.