Radio frequency magnetron sputter‐deposited was investigated as a potential green‐emitting phosphor for thin‐film electroluminescent devices. Thin films ∼0.4 μm thick were tested at a frequency of 60 Hz at 40 V above threshold. The best device values were , , and CIE x = 0.300 and y = 0.664. The films were transparent and smooth, resulting in extremely poor outcoupling of light. This suggests that the internal efficiency of the devices may be significantly higher than reflected by the values of and . Photoluminescent excitation spectra showed a defect state lying 614 meV from the bandedge. Electrical characterization before and after aging showed a very large amount of dynamic space charge was present in as‐deposited devices. This space charge disappeared after aging just 30 min at 3.5 kHz and resulted in a threshold voltage increase from 180 to 220 V.
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Lewis et al. (2000) studied this question.