RADIATIVE AND NON-RADIATIVE RELAXATION OF RARE-EARTH IONS IN MATERIALS FOR OPTOELECTRONIC DEVICES (REVIEW)

Abstract

Electronic configurations of lanthanides and charge states of ions are analyzed. The main models of energy exchange between neighboring of rare-earth (RE) ions are presented, as well as the emergence of cross-relaxation and ap-conversion processes is outlined. The influence of the local crystal field on the splitting of levels of the shielded 4f-shell in RE ions has been established. The splitting of levels the shielded 4f-shell of RE ions in crystal matrices is determined by the combined influence of the Coulomb interaction forces, the spin-orbit interaction, and the weak action of the static crystal field. It is shown that the probability of non-radiative processes can vary by several orders of magnitude within one luminescent center due to the dependence of this process on the size of energy gap of the semiconductor matrix. Based on the construction of mechanisms of radiative and non-radiative relaxation of RE ions, the possibilities of creating effective light-emitting media for optoelectronic technology are considered.