Improvement of crystallographic and electroluminescent characteristics of SrS:Ce thin film devices by post-deposition annealing in Ar-S atmosphere

Abstract

Post-deposition annealing in an Ar-S atmosphere at atmospheric pressure has been demonstrated to improve crystallographic properties and electroluminescent (EL) characteristics of SrS:Ce thin film EL devices. Crystallinity and degree of the orientation of the SrS:Ce thin films with polycrystalline columnar grains are improved by the annealing. It seems that recrystallization takes place between SrS grains. For the annealed devices, charge generation in the SrS:Ce layer is suppressed and relaxation of the phosphor field is decreased. As a result, an instantaneous EL efficiency at the leading edge emission is enhanced. The EL luminance and the average EL efficiency are increased. The annealed SrS:Ce thin-film EL device showed a luminance of 800 cd/m2 and an efficiency of 0.42 lm/W at 1 kHz drive.