30.4: Bright Blue Electroluminescence of BaAl 2 S 4 : Eu Thin Films by Sputtering

Abstract Two different phases of BaAl 2 S 4 : Eu thin films have been obtained by reactive RF magnetron sputtering of Ba x Al: Eu alloy targets. Single‐phased films of either form can be selectively produced over a large area. Both phases are capable of producing bright and efficient thin film electroluminescence but have slightly different emission characteristics and quite different electrical and aging properties. Devices made with these phosphor films on iFire thick dielectric substrates produced ac EL luminance of L 60 over 1000 cd/m 2 at 240 Hz (light pulses) and peak efficiency over 1 lm/W for the α phase, and over 800 cd/m 2 and 0.9 lm/W for the β phase. The processes have been scaled to 34″‐diagonal display panels on a pilot production tool.