Excitation spectrum of a PtLi-related center in silicon

A Pt- and Li-related line spectrum with a series of sharp lines between app roximately 5000 and 8000 cm(-1) has been studied by excitation spectroscopy combined with uniaxial stress. The intensity of the lines are favored when the Pt and Li diffusion was carried out under Li-rich conditions. Phonon r eplicas involving a h omega = 528.6 cm(-1) phonon are detected in the spect rum. Thr phonon is suggested to be Li related and was also directly observe d by local mode vibrational spectroscopy. Yet another set of replicas was o bserved, displaced about Delta = 2229 cm(-1) to higher energies and was int erpreted to originate from shake up effects in the final core state. Uniaxi al stress spectroscopy reveals that shallow donor states are involved in th e final state of the transitions.