How the ZnS:Mn layer thickness contributes to the performance of AC thin-film EL devices grown by atomic layer epitaxy (ALE)

Luminance, efficiency, threshold voltage, and voltage polarity dependence of the light emission have been investigated as a function of the ZnS:Mn layer thickness in ac thin-film electroluminescent (TFEL) devices grown by Atomic Layer Epitaxy (ALE). The crystallinity of the ZnS:Mn layer was studied by X-ray diffraction. The layer of poor crystallinity is about 35 nm and coincides with the dead layer observed in luminance. Luminance is nearly proportional to the ZnS:Mn layer thickness and might indicate a homogeneous excitation throughout the layer at high voltages.