More than 30 years of research on point defects in natural and high-pressure high-temperature synthetic diamond were reviewed with regard to the characterization of chemical vapour deposited material. It was recalled that N was the most common impurity in natural diamond, while H and B were also detected. In high-pressure high-temperature diamond, Ni or Co complexes were also seen. Irradiation produced interstitials and vacancies, and these could help to identify some of the native defects. Chemical vapour deposited diamond could also contain N and B. A prominent defect, which was not normally seen in natural diamonds, was attributed to a Si-vacancy complex. There were some H-related lines in the electron paramagnetic resonance spectra which were peculiar to polycrystalline diamond and appeared to arise near to grain boundaries. Vacancies were seen close to the growth surfaces of very good quality chemical vapour deposited diamonds, although they were not present in the bulk. This could be explained in terms of vacancy migration in natural diamond.

Point Defects in Natural and Synthetic Diamond. A.Mainwood: Physica Status Solidi A, 1999, 172[1], 25-35