The relationship between the photoluminescence intensity due to the W or I1 center, and the O concentration in implanted crystals, was studied. It was found that the photoluminescence intensity of the W center decreased consistently with increasing O concentration, for C-implanted samples with a wide range of C fluences. However, it exhibited no dependence upon the O concentration for samples which were implanted with elements such as H, Si, or heavy metals. On the basis of these results, and of considerations of the reactions of intrinsic defects which were generated by implantation, the photoluminescence W center was attributed to a defect which was composed of Si self-interstitials.

M.Nakamura, S.Nagai, Y.Aoki, H.Naramoto: Applied Physics Letters, 1998, 72[11], 1347-9