The memory effect of ZnS: Mn ac thin-film electroluminescence

The electroluminescence of ZnS: Mn thin-film memory devices is observed to occur in two components, one which is spatially homogeneous and one from localized bright regions less than ∼1 μm in diameter. The brightness-voltage hysteresis, or memory effect, is observed to reside exclusively in the luminescence of the localized bright regions in our devices. It is concluded that the memory effect arises from a negative resistance of a filamentary ac conduction mechanism in these regions.