Formation and structures of multiply-twinned nanoparticles with fivefold symmetry in chemical vapor deposited boron nitride

摘要

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