Carbon Nanotubes

Problems with CNT production
  • Mixture of metallic and semiconducting
  • Alignment and positioning

    • A breakthrough?
  • ST-cut single crystal quartz substrates
  • ethanol/methanol as carbon source
  • Cu nanoparticles as catalysts

    • Results
  • 1.55 to 1.78 nm diameter SWNT
  • 95% semiconducting
  • CNT aligned

    • "We believe that the OH radical from methanol can selectively etch metallic SWNTs because of their smaller ionization potential as compared to semiconducting ones..."
    "We believe that the 36° and 42° Y-cut quartz lattice on the surface is critical for the enrichment of well-aligned, long, and semiconducting SWNTs."



    SEM images show aligned arrays of long nanotubes. Horizontal lines are catalyst lines.

    Lei Ding et al., " Selective Growth of Well-Aligned Semiconducting Single-Walled Carbon Nanotubes," NanoLetters, 9, 800-805 (2009).