Morphology and Structure of BN and B4C Nanocrystals

The morphology and structure of BN and B4C nanocrystals in thin layers produced on Si substrates by plasma-enhanced chemical vapor deposition from triethylamineborane were studied before and after exposure to synchrotron radiation. The as-deposited layers consisted of two types of nanocrystals differing in shape, which all had a defect diamond-like structure. After irradiation, two types of nanocrystals were also observed, but the layers consisted of cubic BN, hexagonal BN, and rhombohedral B4C with lattice parameters differing from those of bulk materials. These results were interpreted as evidence that the irradiated layers contained “centaurs”—intergrowths of different structures with coherent interfaces.