Interpretation of the temperature-dependent behaviour of the emission from isoelectronic tellurium centres in epitaxial ZnSeSUB1-x/SUBTeSUBx/SUB

摘要

The emission from isoelectronic tellurium centres in metal-organic chemical vapour deposition ZnSe1-xTexhas been investigated with photoluminescence and photoluminescence excitation spectroscopy. The emission is dominated by two bands, previously called the S1 and S2 bands and attributed to excitonic emission at isolated tellurium ions or tellurium ion pairs or clusters. The authors account for the temperature-dependent behaviour of these bands with a model in which the tellurium isoelectronic centres behave as spherical potential wells which trap holes via low lying resonant states in the valence band. Changes in intensity of the emission when both bands are observed together have been satisfactorily accounted for within the framework of this model and indicate that the S1 emission results from exciton recombination at tellurium pairs whilst the S2 emission results from recombination at tellurium triplets or larger clusters.