Formation and structures of multiply-twinned nano-particles with five-fold symmetry in chemical vapor deposited boron nitride (BN) were investigated by transmission electron microscopy, electron diffraction and molecular orbital calculation. Sizes and nanostructures of the BN nano-particles were strongly dependent on the deposition temperatures, total gas pressure and synthesis gas. Hexagonal- and rhombohedral-BN were produced at above 1700C and below 1600C, respectively. A 3-dimensional model for the five-fold BN nano-particles was proposed; the five-fold symmetry exhibited some distortion due to the geometrical arrangements along the five-fold axis.

Formation and Structures of Multiply-Twinned Nanoparticles with Fivefold Symmetry in Chemical Vapor Deposited Boron Nitride. T.Oku, K.Hiraga, T.Matsuda, T.Hirai, M.Hirabayashi: Diamond and Related Materials, 2003, 12[10-11], 1918-26