ELECTRON MULTIPLICATION IN ZNS-TYPE ELECTROLUMINESCENT DEVICES

In this paper the influence of electron multiplication in ZnS-type electroluminescence ac devices is studied in a model where the ZnS layer is free from bulk defects. The holes are assumed to recombine with electrons at the interfaces: The two limiting cases of slow and fast hole-electron recombination rate are treated in some detail. The kinetic equations for the electric field and the filling level of interface electrons are established then the charge-voltage characteristics are obtained numerically. An anomalously steep charge-voltage characteristic may be observed for high multiplication rates and slow recombination. In all cases the field is shown to be delayed relative to the current: This phase relationship is related to bulk ideality and allows for qualitative comparisons with experimental data.