Some new photoluminescence features of W line for neutron-irradiated MCz-Si and FZ-Si

Photoluminescence (PL) technique has been applied to study W line (1.018 eV) features for MCz-Si and FZ-Si samples irradiated with neutron dose from 1×10¹⁵ to 3×10¹⁶ n/cm². The energy of quenching process for W line estimated from Arrhenius plot was found to be 0.3 eV what is closed to the activation energy for vacancy diffusion. This suggests that annihilation of W emission is due to vacancy - interstitial recombination assuming that W-line is a tri-interstitial complex, I3. Similar explanation has been suggested in earlier work from positron signal studies. The average thermal energy of dissociation of the defect state responsible for the emission of W line was found to be E = (52+/−5) meV. So we interpret the emission at 1.018 eV as the recombination of an electron and hole at the defect site when one of the particles is strongly bound to the defect with the energy close to 100 meV. This value coincides with the possible donor-like level (0/+) close to valence band edge at Ev+0.1 eV, theoretically predicted for I3 complex.