Structure and chirality distribution of multiwalled boron nitride nanotubes

We report on a high-resolution electron diffraction study of the structure of individual multiwalled boron nitride nanotubes (MW-BNNTs). The tube chirality was determined by electron diffraction. Diffraction patterns were recorded from small sections of the nanotubes, similar to 125 nm long, using the nanoarea electron diffraction technique. Accurate measurements of the MW-BNNT chiral angles and their distribution were made from diffraction patterns. Generally, the tube chiralities within each MW-BNNT are strongly correlated; clustering around a single chirality with a dispersion of a few degrees. Multihelix nanotubes. were rarely observed. Statistics based on 67 nanotubes revealed a dispersion of the chiral angles (alpha) with some preference of tubes in the ranges of 10 degrees <= alpha <= 15 degrees and 25 degrees <= alpha <= 30 degrees. Since various properties of nanotubes depend on the tube structure (diameter and chirality), the results presented here have general significances to nanotube growth and applications. (C) 2005 American Institute of Physics.