Effect of carrier trapping time on performance of alternating-current thin-film electroluminescent devices

In spite of a significant number of studies on memory effect in alternating-current thin-film electroluminescent devices, the phenomenon is still unclear. In the present work we investigate some peculiarities of memory behavior of the devices from the viewpoint of the nonequilibrium carrier trapping time. Applying a combination of unique voltage staircase waveforms, we demonstrate that the degree of memory of the device is determined by the trapping time of the carriers at the insulator–semiconductor interface and the sulfur vacancy (Vs) concentration in the bulk of the active layer. We also show that separating electrons and holes before the pulse arrival can increase the effective field across the phosphor layer.

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