Morphology and crystalline-phase-dependent luminescence of Li-doped Gd2O3:Eu3+ thin films grown by pulsed laser deposition

Gd2O3:Eu3+ and Li-doped Gd2O3:Eu3+ luminescent thin films have been grown on Si(100) substrates using pulsed laser deposition. The films grown at different deposition conditions show different crystalline and morphology structures and luminescent characteristics. Although both cubic and monoclinic crystalline structures were observed in both Gd2O3:Eu3+ and Li-doped Gd2O3:Eu3+ films, the cubic structure becomes more dominant for Li-doped Gd2O3:Eu3+ films. The photoluminescence brightness data obtained from Li-doped Gd2O3:Eu3+ films indicate that Si(100) is a promising substrate for growth of high-quality Li-doped Gd2O3:Eu3+ thin-film red phosphor. In particular, the incorporation of Li+ ions into the Gd2O3 lattice induced a change of crystallinity and enhanced surface roughness. Two major factors to determine photoluminescence brightness for Li-doped Gd2O3:Eu3+ films were crystalline phase and surface roughness. The highest emission intensity was observed with Gd1.84Li0.08Eu0.08O3, whose brightness was a factor of 2.1 larger than that of Gd2O3:Eu3+ films. This phosphor is promising for applications in flat-panel displays.