Electroluminescent Devices With CaS:Eu2+ Active Layer Grown by R.F. Reactive Sputtering
Over the past few years, intensive work has been made to achieve color thin film electroluminescent (E.L.) devices. Alkaline-earth sulphide CaS and SrS are the most promising materials for red and blue colors [1, 2, 3 ]. Nowadays, the active layer CaS:Eu2+ is the material of choice which emits the fundamental red color. This layer is usually grown by electron-beam evaporation [ 2, 3 ] but it is necessary to heat the substrate up to a 680°C temperature, which leads to technological difficulties. R.F. reactive sputtering technology can overcome these problems [ 4,5 ]. We report here on the optimization of growth conditions for CaS:Eu2+ thin films by this technique. We also report the results obtained when this active layer is integrated in E.L. devices.
KeywordsActive Layer Space Charge Region Trap Density Electroluminescent Device Reactive Sputtering
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