ZnGa[sub 2]O[sub 4]:Mn phosphors for Thin-Film Electroluminescent Displays Exhibiting Improved Brightness

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Abstract
Thin films of ZnGa2O4:MnZnGa2O4:Mn films have been deposited by radio frequency magnetron sputtering in order to study the effects of annealing temperatures less than 1000°C 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.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⩾750°C,T⩾750°C, a single emission band at 504 nm was observed. Emission wavelength was independent of annealing temperature. The electroluminescent brightness of the devices peaked at an annealing temperature of 900°C. Peak brightness and efficiency were 350 cd/m2cd/m2 and 0.55 lm/W at 60 Hz, and 1500 cd/m2cd/m2 and 0.30 lm/W at 600 Hz. These high brightness values have been attributed to the roughness of the substrates. © 2001 The Electrochemical Society. All rights reserved.