It was noted that diamond contained only one atomic species, and that the effects of isotopic substitution at the self-interstitial could be understood quantitatively. It was pointed out that there were nevertheless surprising gaps in current understanding. At low temperatures, in pure diamond, the rates of production of neutral vacancies and self-interstitials were equal. However, when the irradiation temperature exceeded about 120K there was a significant loss of observable Io centres; via an unknown process. The reaction kinetics of Io were not understood, and complications arose from the existence of barriers to reactions between defects. These resulted in various metastable configurations. In N-doped diamond, there was evidence of a considerable reduction in the rate of correlated recombination in the locality of the N impurity. It was concluded that this had possible implications for the radiation hardness of strained diamond.

Interstitials, Vacancies and Impurities in Diamond. G.Davies, B.Campbell, A.Mainwood, M.Newton, M.Watkins, H.Kanda, T.R.Anthony: Physica Status Solidi A, 2001, 186[2], 187-98