Using the spin-dependent microwave photoconductivity detection of electron paramagnetic resonance, a new low-symmetry configuration of a complex which contained an interstitial Si and two C atoms was found in irradiated Si. This configuration could be considered to be an intermediate state which formed during annealing of the substitutional C–interstitial Si–substitutional C (Cs–Sii–Cs) complexes, giving rise to the Si-PT4 spin-1 electron paramagnetic resonance spectrum of monoclinic symmetry which transformed, below 20K, into the new triclinic spin-1 spectrum labeled Si-WL5. The identification of the Si-PT4 and Si-WL5 spectra was made using Si enriched with the 13C isotope.

New Low Symmetry Configuration of the Two Carbon–Interstitial Silicon Complex in Irradiated Silicon. R.Laiho, M.P.Vlasenko, L.S.Vlasenko: Solid State Communications, 2002, 124[10-11], 403-6