Structure and defects of vapor-phase-grown diamond nanocrystals

Diamond nanocrystalline films are prepared by the ion bombardment-assisted gas vapor synthesis technique. The phase quality, morphology and microstructure of the films are investigated by means of Raman spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The grain size in the film ranges from several nanometers to several tens of nanometers. There is a high density of lattice defects, mainly stacking faults and twin boundaries in the nanocrystals. Lattice distortions, vacancies, and dislocations are observed. The growth of nanocrystals and the mechanism of defect formation are discussed in light of the ion impact effect.