Optical studies of irradiated crystalline silicon doped with carbon and lithium

Many lithium and carbon related photoluminescence lines are observed in irradiated crystalline silicon doped with lithium and carbon which were not reported previously. The half-time for the thermal decay of the absorption intensities of the G line al 969 meV and the Q line at 1045 meV is less than 15 min, which is smaller than the published data. We believe that the fast decay of the absorption intensities of both centres is due to the switching between different charge states. The radiation damage 4Li-V defect, like the dicarbon centre, can have different charge stales. New lithium and carbon related donor or acceptor systems may be created after annealing the irradiated samples at 230 degrees C.