EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE STUDIES OF LUMINESCENT CENTERS IN II-VI THIN-FILMS

Extended x-ray absorption fine structure (EXAFS) was used to determine the local structure of luminescent centers in electroluminescent thin-films: in Mn- and Tm-doped zinc sulfide as well as in Tb- and Ce-doped calcium sulfide and strontium sulfide. EXAFS measurements were carried out using the electron-yield detection method. While Mn enters a substitutional site, the larger Tm ion is associated with oxygen and forms TmO+ polycations. In CaS the rare-earth dopants replace Ca2+ ions in the lattice and no oxygen was found in their environment.