Photoluminescence of transition metal complexes in silicon

Results of luminescence studies on silicon doped with the 3d transition metals are reviewed. Spectra are observed after V, Cr, Mn, Fe, and Cu diffusion. We discuss the problems of center identifications, using the example of the CrB-pair luminescence. Level schemes for the optical transitions are discussed and correlated with electrical level positions of TM defects. Luminescent centers can be divided into two classes: CrB,CrGa, and Mn₄ are effective recombination centers with low quantum efficiencies, whereas Fe and Cu associated spectra show characteristics of exciton decay at isoelectronic centers, e.g. show a high quantum efficiency. The phonon structure of the spectra is discussed, and it is shown that the local mode energies of the centers follow a systematic trend.