Two optical bands, due to short-term Se diffusion, were studied by using photoluminescence techniques. The bands had similarities to 2 previously reported Se-related bands, but were shifted in energy. The present Se-related bands were observed only after short-time diffusion. They were also observed after 540s, but not after 1080s, diffusion at 1100C. One of the bands consisted of 3 sharp zero-phonon lines, whereas the other exhibited only broad structures. A thermalization study indicated that the sharp lines were due to spin-singlet and spin-triplet initial states; as were previously studied Se and S bands. The spin-triplet state appeared to be split into 3 components, and was interpreted as being due to a near-axial symmetry crystal field. The luminescence from 2 of the states was directly observed as zero-phonon lines, whereas only a phonon replica of the third one was detected. The excitation spectrum of the neutral isolated Se double donor was observed by means of photoconductivity measurements. These established that substitutional Se was present in detectable amounts in the samples; even the 540s ones above. It was suggested that the photoluminescence bands were related and/or were precursors of the previously reported bands that were observed after considerably longer diffusion times.

A Photoluminescence Study of Selenium-Diffused Silicon X.Zhang, M.Kleverman, J.Olajos: Semiconductor Science and Technology, 1999, 14[12], 1076-9