Ultrahigh-Vacuum-Assisted Control of Metal Nanoparticles for Horizontally Aligned Single-Walled Carbon Nanotubes with Extraordinary Uniform Diameters

作者：Ago Hiroki^*; Ayagaki Takafumi; Ogawa Yui; Tsuji Masaharu

来源：Journal of Physical Chemistry C, 2011, 115(27): 13247-13253.

DOI：10.1021/jp2038448

Uniform diameter, horizontally aligned single-walled carbon nanotubes (SWNTs) are grown on sapphire substrate through the control of Fe nanoparticle size by annealing in ultrahigh vacuum (UHV). We find that thermal annealing in UHV reduces the Fe nanoparticle size and significantly narrows their size distribution. These size-controlled Fe nanoparticles enable the catalytic growth of uniform-diameter SWNTs while maintaining their horizontal alignment. Systematic analyses of Raman radial breathing modes with three laser wavelengths indicate that similar to 76% of the horizontally aligned SWNTs have diameters in the range of 1.3-1.4 run under optimized annealing conditions. Longer UHV annealing induces the increase in the Fe nanopartide size, giving large-diameter SWNTs. Precise correlation between the metal nanoparticle size and SWNT diameter is demonstrated. Effects of UHV annealing on the nanoparticle size are,discussed in terms of evaporation, subsurface diffusion, and surface precipitation of catalyst metals.

• 出版日期2011-7-14