Nonmonotonic behavior of luminescence characteristics of fine-dispersed self-propagating high-temperature synthesized ZnS:Mn depending on size of its particles

We performed a comparative analysis of photoluminescence spectra of micro- and meso-fractions of powdery ZnS:Mn obtained by self-propagating high-temperature synthesis. It was found that manganese ions take part in excitation of ZnS self-activated luminescence. From the data on photoluminescence excitation spectra it was established that excitation of emitting Mn ion in ZnS:Mn meso-fraction is realized with participation of sensitizers (MnZn) and without charge carriers excited at interband absorption. This is explained within a model according to which, at particles size smaller than double length of the space charge region, the particle potential barrier becomes lower and Fermi level decreases owing to summation of space charge regions of opposite particle surfaces, i.e., the depletion region extends over the total particle volume.