ZnGa2O4:Mn phosphors for thin-film electroluminescent displays exhibiting improved brightness

Thin films of ZnGa2O4:Mn films have been deposited by radio frequency magnetron sputtering in order to study the effects of annealing temperatures less than 1000 degreesC on the thin-film electroluminescent properties. Energy-dispersive X-ray compositional analysis showed a loss of zinc during sputtering, with the film composition being Zn0.9Mn0.03Ga2O4. All films showed strong (111) and (222) X-ray reflections relative to the power standard. As the annealing temperature was raised, the texture rotated toward that of the powder material. The as-deposited films showed no photoluminescence; however, once annealed at T greater than or equal to 750 degreesC, a single emission band at 504 run was observed. Emission wavelength was independent of annealing temperature. The electroluminescent brightness of the devices peaked at an annealing temperature of 900 degreesC. Peak brightness and efficiency were 350 cd/m(2) and 0.55 lm/W at 60 Hz, and 1500 cd/m(2) and 0.30 lm/W at 600 Hz. These hi.-h brightness values have been attributed to the toughness of the substrates. (C) 2001 The Electrochemical Society.