DOPED AMORPHOUS AND CRYSTALLINE GALLIUM OXIDES, ALKALINE EARTH GALLATES AND DOPED ZINC GERMANATE PHOSPHORS AS ELECTROLUMINESCENT MATERIALS

摘要

New oxide phosphors based on doped gallium oxides, alkaline earth gallates and germanates for electroluminescent display materials. Bright orange red electroluminescence has been obtained in amorphous and crystalline oxides Ga2O3:Eu for the first time. SrGa2O4 and SrGa4O9 doped with 1-8 mole % of Eu and Tb, CaGa2O4, Ca3Ga2O6 and CaGa4O7 doped with 1-4 mole % of Eu, Tb, Pr and Dy, BaGa2O4 doped with 1-2 mole % of Eu and Tb, have been prepared using RF magnetron sputtering onto ceramic dielectric substrates and annealed at 600 °C - 950 °C in air or Ar for 1-2 hours. Bright electroluminescent (EL) emission was obtained with wavelengths covering the visible sprectrum from 400 to 700 nm, and infrared emission above 700 nm with spectral peaks characteristic of rare earth transitions. The films of CaGa2O4 with 1 mole % Eu achieved 22 fL (75 cd/m2) at 60 Hz and had a maximum efficiency of 0.2 lm/w for red emission. An amorphous thin film of Ca¿3?Ga2O6 with 2 mole % Eu achieved 34 fL in red EL at 60 Hz when annealed at 600 °C. SrGa2O4 with 1 mole % Eu and 4 mole % Tb yielded 'white' phosphor having red, green and blue emission (13 fL at 60 Hz), and SrGa2O4 with 8 mole % Tb resulted in a blue and green phosphor measuring 30 fL at 60 Hz. Zn2Si0.5Ge0.5O4 containing Mn was sputtered using magnetron RF sputtering onto ceramic dielectric substrates and annealed at 700 °C for 1 hour in air or argon. Bright green (540 nm) emission was obtained in electroluminescence: 110 fL (377 cd/m?2¿) at 60 Hz with a maximum efficiency of 0.9 l/w. Moderately bright red emission (640 nm) was also obtained.