Stress-stimulated luminescence from ZnAl2O4:Mn

We have investigated the stress-stimulated luminescence (SSL) from ZnAl2O4:Mn. Two kinds of ZnAl2O4:Mn samples were synthesized at different reduction conditions to clarify the influence of the structure defects on the SSL property. The SSL intensity was found to be greatly increased by reducing ZnAl2O4:Mn at a high temperature of 1300 °C. The luminescence integrated intensity was about two magnitudes larger than that of conventional ZnAl2O4:Mn. This enhancement is attributed to a large number of trapped carriers in the reduced ZnAl2O4:Mn from the results of thermoluminescence. The SSL spectrum was consistent with the photoluminescence spectrum as well as the afterglow one. It is suggested that the trapped carriers can be excited by stress, and the resultant recombination between excited electrons and holes give rise to an energy which can be transferred to Mn2+ centers to create emission according to the transitions of T14 to A16.