Optical properties of sol-gel derived Y_2O_3:Eu~(3+) thin-film phosphors for display applications

摘要

Y_2O_3:Eu~(3+) thin-film phosphors were grown on sapphire substrates using a simple sol-gel process. The films were annealed at various temperatures between 700 and 1400℃ for 2 h in air after deposition. The optical properties, morphologies and crystallographic structures of the Y_2O_3:Eu~(3+) thin films are characterized and discussed. The sol-gel process enabled the synthesis of efficient Y_2O_3:Eu~(3+) thin-film phosphors with good optical properties, high crystallinities and smooth morphologies. The cathodoluminescence (CL) and photo luminescence properties of these Y_2O_3:Eu~(3+) thin films depend principally on the film thickness and annealing temperature. The Y_2O_3:Eu~(3+) thin film annealed at 1200℃ had a thickness of ～ 1.7 μm and exhibited a CL luminance of ～ 150 cd/m~2 and Commission International del'Eclairage coordinates of (0.64, 0.35) under 5 kVe-beam excitation at 5 μA/cm~2. A significant improvement (by a factor of about 2) was found in the aging characteristics of the Y_2O_3:Eu~(3+) thin-film phosphors under 5 kV CL excitation compared to those of powder phosphors.