Aging of ZnS:Mn ALE ac thin-film electroluminescent devices

The aging behavior of ZnS:Mn ACTFEL devices, driven with asymmetrical voltage waveforms, was analyzed. Samples were aged with asymmetrical waveforms, so a time-averaged electric field exists in the phosphor layer during operation. Transient measurements were used to determine the voltage polarity dependence of the aging process. While with symmetrical aging and waveforms which cause a positive time-averaged field the positive polarity is mainly affected, a negative time-averaged field affects both polarities. A simple model to explain these measurements is proposed.