Efficiency of cerium-doped yttrium-aluminum garnet as a phosphorescent source

The rare earth ion doped yttrium aluminum garnet crystals or YAG are widely used as lasing materials and for other quantum electronic device applications. Robbins et al. and Gibbons et al. showed that at least one type of defect is responsible for the wide 300 nm luminescence band observed in photoluminescence and cathodoluminescence. These defects, which are inherent to pure YAG, influence the excitation energy transfer to the rare earth ions, the luminescence kinetics, etc. This ensures the importance of detailed information about the structure of these defects. To explain the temperature dependence of the luminescence kinetics and the stationary luminescence spectra, Robbins et al. proposed the existence of at least three types of the centers. They explained the temperature dependence of the luminescence decay times to be a result of the consequent ionization of these centers. The aim of the present work is to prove that the experimental results of Robbins et al. can be explained in the framework of the model incorporating centers of one type only. These are electrons bound by the oxygen vacancy.