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 pr operty. The SSL intensity was found to be greatly increased by reducing ZnA l2O4:Mn at a high temperature of 1300 degreesC. The luminescence integrated intensity was about two magnitudes larger than that of conventional ZnAl2O 4:Mn. This enhancement is attributed to a large number of trapped carriers in the reduced ZnAl2O4:Mn from the results of thermoluminescence. The SSL s pectrum was consistent with the photoluminescence spectrum as well as the a fterglow one. It is suggested that the trapped carriers can be excited by s tress, and the resultant recombination between excited electrons and holes give rise to an energy which can be transferred to Mn2+ centers to create e mission according to the transitions of T-4(1) to (6)A(1). (C) 2001 America n Institute of Physics.