Helicity Distributions of Single-Walled Carbon Nanotubes and Its Implication on the Growth Mechanism

Single-walled nanotubes (SWNT) have attracted significant attention because of the substance’s superior crystal quality, high thermal conductivity and current carrying capacity, thus emerging as an attractive material for nanoelectrics. To optimize the selection of SWNT structures in large-scale synthesis, an understanding of their growth mechanism is necessary. We report studies of the helicity distributions of SWNT using electron nanodiffraction. The overall statistical distribution of helicity has peaks at 0° and 30°. The peak evident at 0° was found to be a sharp local maximum, while the peak at 30° was broader. We also found that the helicity distribution varies from region to region of micrometer size. This observation indicates that local environment affects nanotube growth, resulting in different structural distributions.