SrS:Ce thin-film electroluminescent devices prepared by electron beam evaporation under the controlled high sulfur vapor pressure

Abstract

To improve guality of SrS:Ce thin films and to improve EL characteristics ,the SrS:Ce thin films were prepared by using electron-beam evaporation under the controlled sulfur vapor pressure. The maximum luminance(Lmax) of 500〜600cd/m2 was obtained for the EL devices prepared at substrate temperature of 500-570℃ under sulfur vapor pressure of 2-4 × 10-4Torr, although the crystallinity of the films deposited at 550℃ was the best. By annealing of the SrS:Ce thin films in Ar-S atmosphere at 630℃ ,Lmax was increased and reached to 1000cd/m2. X-ray diffraction intensity and photoluminescent intensity were also increased by annealing. Surface morphology and cross-sectional view of the annealed films observed by Scanning Electron Microscope were also different compared with those of as-deposited films.