Fabrication of Y3Al5O12:Eu thin films and powders for field emission display applications

Thin films of Y3Al5O12:Eu (YAG) were spin coated on different substrates from sols. The precursor solution was made from organic precursors by combining stoichiometric ratios of Y(III) iso-propoxide, Al(tri Sec-butoxide) and Eu(III) acetyl acetonate. Sol-gel derived thin films and powders are non-crystalline. Powder samples calcined at 650 degrees C for 5 h show the characteristic X-ray diffraction pattern for the YAG phase. Similarly, the thin film samples annealed at 600 degrees C for 5 h also show YAG phase in the XRD. The emission spectra were measured for both the powder and thin-film samples. Scanning electron microscopy for the powder samples show that the particles are reasonably crystallized with a particle size of 5 mu m. The spectral response and out gassing characteristic of the new, low voltage YAG thin films mainly used for application in the field emission flat panel displays are also measured. The cathodoluminescent materials were tested with electron beam excitation at currents of up to 50 mu A within the 3000-8000 V range (medium voltage range). The spectral coordinates with minimal optimization as compared with industrially manufactured P22 phosphors at low voltage operation are reasonable.