The emission from iso-electronic Te centers in metalorganic chemical vapor deposited material was investigated by means of photoluminescence excitation spectroscopy. It was found that the emission was dominated by 2 bands which had previously been called S1 and S2, and had been attributed to excitonic emission at isolated Te ions or Te ion pairs or clusters. The temperature-dependent behavior of these bands was accounted for in terms of a model in which the Te iso-electronic centers behaved as spherical potential wells which trapped holes via low-lying resonant states in the valence band. Changes in the intensity of the emission, when both bands were observed together, were satisfactorily accounted for within the framework of the model, and indicated that the S1 emission resulted from exciton recombination at Te pairs, while the S2 emission resulted from recombination at Te triplets or larger clusters.

K.Dhese, J.Goodwin, W.E.Hagston, J.E.Nicholls, J.J.Davies, B.Cockayne, P.J.Wright: Semiconductor Science and Technology, 1992, 7[9], 1210-6