The characteristics of SrS:Ce thin film electroluminescent devices

SrS:Ce thin alms were fabricated by electron beam evaporation under several conditions such as substrate temperature, deposition rate and sulphur pressure during evaporation. The relationship between the quality of phosphor layers and the luminance of EL (electroluminescent) devices investigated. The bigger dead layer of SrS:Ce phosphor layer produced the larger spike current when bipolar trapezoidal voltage pulses were loaded on the SrS:Ce TFEL (thin film electroluminescent) devices. The low crystallinity of the phosphor bulk layer reduced the spike current. The magnitude of spike current is limitted by a balance between the number of hot electrons injected into the phosphor layer from the phosphor-insulator interface and the number of hot electrons captured by defect levels in phosphor layer. The luminance of EL devices is determined by the effective number of hot electrons and the crystallinity of phosphor layer.