Interstitials, vacancies and impurities in diamond

Diamond is a very simple crystalline system, and we would expect that the effects of radiation damage should be easily understood. As an example of its simplicity, we note that diamond contains only one species of atom, and we show that the effects of isotopic substitution at the self-interstitial can be understood quantitatively. However, there are surprising gaps in our current Understanding. At low temperatures, and in pure diamond, the rates of producing neutral vacancies and self-interstitials are equal. but when the irradiation temperature exceeds similar to 120 K there is a significant loss of observable I-0 centres by a process that is not yet known, The reaction kinetics of I-0 are not Vet understood, and one complication is the existence of barriers to reactions between defects. which will result in various metastable configurations. In nitrogen-doped diamond, there is evidence for a considerable reduction in the rate of correlated recombination in the locality of the nitrogen impurity, which has possible implications for the radiation hardness of strained diamond.