TEMPERATURE-DEPENDENCE OF PHOTOLUMINESCENCE IN SRSEU2-FILMS(, SM3+ THIN)

Details of photoluminescence spectra of SrS singly and doubly doped wi th Eu2+ and Sm3+ thin films were obtained at various temperatures betw een 10 and 300 K. From band broadening and shifting a strong electron- lattice interaction was observed for the Eu2+ ionic transition. The te mperature dependence of the emission intensity for different excitatio n energies in the range 2.84-5 eV leads to the identification of diffe rent transition mehanisms, namely, ionic transition and photostimulate d ionization. An anomalous emission center was observed at 1.88 eV, wh ich is proposed to be an exciton trapped at the Eu2+-V(Sr) center.