Simulation of Luminescence-Intensity Deterioration Properties for ZnS:Cu Powder Electroluminescence Device

Luminesccncc-intensity deterioration properties for a ZuS:Cu powder EL device have becn simulated with a model that the powder EL device is composed of many small luminesccnt cells and the luminesccnce in such a small cell is caused by electron injcction from the phosphor surface with tunneling mechanism. Total lumincsccnce properties which can qualitatively explain expcrimental data for the powder EL device， are thcoretically obtained by assuming that an effective thickness of phosphor of a cell in the powder EL device is distributed in the Gaussian distribution function. Experimental results for lumincscence-intensity deterioration for the powder EL device are also explaincd by assuming that a cell with the smaller effective thickness of phosphor is damaged with the shorter operation time because of the higher elcctric field in such a cell