The production and annealing stages of the self-interstitial (R2) defect in diamond

We report on the production rate of the neutral (0 0 1)-split self-intersti tial (measured via the electron paramagnetic resonance (EPR) concentration of the R2 defect) in type IIa diamond irradiated at a controlled and measur ed sample temperature in the interval 110-350 K with 2 MeV electrons and a beam flux of 7.5 x 10(13) electrons cm(-2) s(-1). On annealing at similar t o 700 K, we find that the neutral (0 0 1)-split self-interstitial (R2) defe ct is mobile and anneals out with an associated energy of 1.6(2) eV and som e loss of neutral vacancies. A significantly reduced production rate of R2 in the temperature interval 110-350 K is suggestive of a radiation enhanced annealing process. (C) 1999 Elsevier Science B.V. All rights reserved.