High brightness red electroluminescence in CaS:Eu thin films

Abstract

The crystallinity and luminescent property were studied on evaporated CaS:Eu thin films. The orientation of the film strongly depends on substrate temperature. Distinct orientation was not observed in films deposited below 600°C. Above 600°C, the films tend to have a (111) orientation. The red emitting electroluminescent device with CaS:Eu active layer prepared at 680°C which is strongly oriented to the [111] direction shows the brightness of 180 cd/m2 under 1 kHz alternate excitation.