ZnS:Mn Thin Film Electroluminescent Devices Having Doubly-Stacked Insulating Layers

Abstract

ZnS:Mn thin film electroluminescent devices having doubly-stacked insulating layers have been developed. The insulating layer consists of electron-beam evaporated Ta 2 O 5 , and rf-magnetron sputtered SiO 2 stacked layers. It is concluded that the thick semi-insulating Ta 2 O 5 films (1000 nm) deposited on both sides of the ZnS:Mn active layer act as a carrier injctor for electroluminescence and the thin insulating SiO 2 films (80 nm) inserted between the electrodes and Ta 2 O 5 films act as a carrier limiter. The breakdown voltage margin defined by ( V bd - V th )/ V th was improved from 15% to more than 80% by introducing thick semi-insulating Ta 2 O 5 films.