Time-resolved pulsed DC electroluminescence studies in ZnS:Mn, Cu-powder Phosphors

Time-resolved studies of pulsed dc electroluminescence from ZnS:Mn, Cu-powder phosphors are reported. Emission bands from the orange Mn²⁺transition and a very broad band extending from 1.5 to 3.6 eV are detected. The broad band, attributed to higher conduction band transitions of hot electrons, is used as a probe of avalanching in the devices. Study of the onset of the Mn²⁺luminescence provides evidence for direct impact excitation of Mn²⁺ions. Current densities much higher than expected for uniform current flow are deduced from the rate of increase of luminescence rise transients.