Radiative Transitions in Sm2+ Doped ZnAl2Se4 and KCl Crystals

Abstract

Photoluminescence spectra of ZnAl2Se4:Sm2+ and KCl:Sm2+ due to the processes of charge carriers recombination from levels 5Dj,5Lj,5Gj and 5Hj (4f55d1) on levels 7Fj of samarium ions were investigated. The broad photoluminescence band at energies 1.6 - 1.9 eV due to optical transitions of electrons form 4f shell of samarium ions to 1s level of vacancies was discovered. Emitted energy of it was absorbed by transitions from 7Fj to 5Dj levels. An up-conversion process - electron excitation form 7Fj levels to 5D0, 5D1, 5D2 levels with simultaneous electron transitions to higher energy states 5D3, 5D4, 5Lj, 5Gj, 5Hj with subsequent recombination to 7Fj levels with energy emission in short-wavelength region were found out and investigated.