Photoluminescence characteristics of Li-doped Y₂O₃:Eu³thin-film phosphors on sapphire substrates

Abstract

Y2O3:Eu3+ and Li-doped Y2O3:Eu3+ luminescent thin films have been grown on sapphire substrates using a pulsed laser deposition technique. The thin-film phosphors were deposited at a substrate temperature of 600°C under the oxygen pressures of 100, 200, and 300 mTorr. The films grown under different deposition conditions have been characterized using microstructural and luminescence measurements. The crystallinity and photoluminescence (PL) of the films are highly dependent on the oxygen pressure. The PL brightness data obtained from Y2O3:Eu3+ films grown under optimized conditions have indicated that sapphire is a promising substrate for the growth of high-quality Y2O3:Eu3+ thin-film red phosphor. In particular, the incorporation of Li+ ions into Y2O3 lattice could induce a remarkable increase of PL. The highest emission intensity was observed with LiF-doped Y1.84Li0.08Eu0.08O3 (Y2O3LiEu), whose brightness was increased by a factor of 2.7 in comparison with that of Y2O3:Eu3+ films. This phosphor may hold promise for application in flat-panel displays.