On the formation of nanoparticles exhibiting fivefold symmetry in hexagonal boron nitride deposited by chemical vapor deposition

摘要

The microstructure of nanoparticles exhibiting fivefold symmetry in hexagonal boron nitride (h-BN) was comparatively studied by transmission electron microscopy, scanning electron microscopy and X-ray powder diffraction. Multiply twinned particles were observed after mechanical thinning of polycrystalline h-BN substrates at room temperature. Such particles have not been found in freshly cleaved samples, samples annealed at 1100°C and samples from the same material prepared as a powder. It is suggested that the formation of fivefold particles is a result of micromechanical twinning of the hcp structure rather than growth twinning.