Low‐temperature photoluminescence studies of ion‐implanted and rapid thermal annealed or pulsed‐laser‐annealed Si are reported. The samples were implanted with As, P, Sb, or B. The luminescence spectra of the pulsed‐laser‐annealed samples show strong sharp luminescence lines from radiation induced defects, whereas in samples implanted with As, P, or B and rapidly annealed with an arc lamp a very clean spectrum without any defect luminescence is observed. This indicates a very low defect concentration in the lamp annealed material. In Sb‐implanted lamp‐annealed samples, however, a broad defect luminescence band appears as the temperature is raised and which varies in shape as a function of the annealing temperature. This band is probably due to Sb agglomerates.