Boron-induced dramatically enhanced growth of diamond grains in nanocrystalline diamond/hydrogenated amorphous carbon composite films deposited by coaxial arc plasma deposition

Boron-doped nanocrystalline diamond/hydrogenated amorphous carbon composite films were prepared by coaxial arc plasma deposition. The Xray diffraction measurement exhibited that the diamond grain size is remarkably increased from 2nm (undoped films) to 82 nm and the lattices of the grains are dilated accompanied by the incorporation of boron atoms into the lattices. The near-edge X-ray absorption fine-structure showed a weak exciton peak of diamond due to the enlarged grains. The enhanced growth mechanism is discussed on the basis of a defect-induced diamond growth model.