Abstract
A systematic study has been made of some of the properties of R2, the most dominant paramagnetic defect produced in type-IIa diamond by electron irradiation. R2 has been produced in high-purity synthetic diamonds, which have been irradiated with 2 MeV electrons in a specially developed dewar, allowing irradiation down to a measured sample temperature of 100 K, at doses of to electrons The production rate of vacancies was the same for irradiation at 100 K as at 350 K, but the production rate of the R2 electron-paramagnetic-resonance (EPR) center is at 100 K and only at 350 K. Measurements have been made of the angular variation of the EPR linewidth, hyperfine structure of samples grown with enriched isotopic abundance of and of the EPR of samples annealed under uniaxial stress (for which a special equipment was developed). A combination of these data with the previously measured data has shown that R2 is the neutral -split self-interstitial. This is an identification of an isolated stable self-interstitial in a group IV material. This shows that the self-interstitial is not mobile in type-IIa diamond under normal conditions (i.e., without the irradiation) until the annealing temperature of 700 K.
- Received 6 May 1999
DOI:https://doi.org/10.1103/PhysRevB.61.3863
©2000 American Physical Society