Variation of the electroluminescence spectra of ZnZ:Mn thin-film emitters depending on the excitation level

The electroluminescence (EL) spectra of ZnS:Mn thin-film emitters measured in various regions of the luminance wave exhibit, besides the bands characteristic of the intracenter emission from Mn2+ ions, additional EL bands peaked at ∼530 and ∼655 nm, which are probably related to the trapping of free electrons on deep centers formed by the sulfur vacancies V S 2+ and V S + . These traps may lead to the formation of a negative bulk charge in a near-cathode region, inducing a decrease in the growth rate (or even a drop) of current through the phosphor, as well as a decay of instantaneous luminance.