Enhanced luminescence of Gd_2O_3:Eu~(3+) thin-film phosphors by Li doping

摘要

Gd_2O_3 :Eu~(3+) and Li-doped Gd_2O_3 :Eu~(3+) luminescent thin films have been grown on Al_2O_3 (0001) substrates using pulsed-laser deposition. The films grown under different deposition conditions show different microstructural and luminescent characteristics. Both cubic and monoclinic crystalline structures were observed in Gd_2O_3: Eu~(3+) films, but only the cubic crystalline structure was observed for Li-doped Gd_2O_3:Eu~(3+) films grown under certain condition. The photoluminescence (PL) brightness data obtained from Li-doped Gd_2O_3:Eu~(3+) films indicate that sapphire is a promising substrate for growth of high-quality Li-doped Gd_2O_3:Eu~(3+) thin-film red phosphor. In particular, incorporation of Li~+ ions into the Gd_2O_3 lattice can induce a remarkable increase of PL. The highest emission intensity was observed with LiF-doped Gd_(1.84)Li_(0.08)Eu_(0.08)O_3, whose brightness was a factor of 2.3 larger than that from Gd_2O_3: Eu~(3+) films. This phosphor is promising for applications in flat-panel displays.