ZnS:Mn薄膜のエレクトロルミネセンス Electroluminescence in ZnS : Mn Films

ZnS : Mn powder phosphors were prepared by firing of ZnS (99.9%)-Mn. MnCl_2 or Mn (CH_3COO)_2 was utilized as Mn activator. The concentration of Mn was 0.1 wt.%, 0.55 wt.%, and 5 wt.%. For the fired ZnS : Mn powder, a broad-band photoluminescent emission peaking at 5800A was observed by ultraviolet excitation. Structure of EL cell used in this study was a (Al)-(ZnS : Mn)-(In-Sn oxide) layer type. The films were deposited by evaporation of ZnS : Mn materials from quartz crucible in vacuum. A broadband electroluminescent emission peaking at 5800A was observed under electric field more than 2-7×(10)^5 V/cm applicable to ZnS : Mn layer. EL brightness follows the relation B∝V-1/2 and also increases with frequency of AC voltage. Electroluminescent mechanism is believed to the direct impact ionization of Mn centers.