一种新结构中ZnSe薄膜电致发光特性研究

Electroluminescence of ZnSe Thin Film with a New Devices Structure

用电子束蒸发的方法制备了一种新的ITO/SiO2/ZnSe/SiO2/Al薄膜电致(TFEL)发光器件。在交流电压驱动下,其有2个发光峰,分别位于466nm和560nm。通过研究器件(PL)激发(PLE)谱、光致发光、EL发光以及EL发光强度随驱动电压和频率的变化发现,器件的发光来源于ZnSe的带边发射和自激活发光中心。器件的发光机理与一般的无机电致发光有所不同。这里,SiO2作为电子加速层,ZnSe作为发光层,电子在SiO2层中的高电场作用下被加速到很高的能量,然后直接碰撞激发ZnSe分子使其发光。这种发光现象被称为固态类阴极发光。

A novel thin film electroluminescence (TFEL) device using ZnSe as light emitting layer and SiO2 as electron accelerating layer was fabricated by electron-beam evaporation. When the device excited by a sinusoidal voltage with frequency at 2000 Hz, two peaks (466 nm and 560 nm) were observed. The photoluminescence (PL), photoluminescence excitation (PLE) spectra, EL and the dependence of EL intensity on applied voltage and frequency were investigated. The luminescence of ZnSe thin film is attributed to the edge emission and recombination of electrons in conduction band with the holes trapped in the native defective centers. Here, the electrons are accelerated in SiO2 instead of in ZnSe, the luminescence of which is named cathodoluminescent-like emission.