Recombination-enhanced diffusion of self-interstitial atoms and vacancy–interstitial recombination in diamond

Abstract

In this paper we report the results of EPR and optical studies on vacancies and interstitials produced in type IIa diamond irradiated with 2-MeV electrons at temperatures between 90 and 900 K. Post-irradiation annealing studies at temperatures up to 1900 K were also performed. Data showing recombination-enhanced diffusion of self-interstitial atoms in diamond is presented and our analysis of the phenomena leads us to the conclusion that a highly mobile interstitial I* (possibly a charged/neutral Td interstitial) is produced by electronic excitation and/or charge transfer. We estimate that the migration energy for I* is 0.3 eV. No evidence for vacancy recombination-enhanced diffusion was observed. The experimental data confirms that there is a significant barrier to vacancy–interstitial recombination in diamond.