Growth and luminescence properties of Eu-doped (Na0.425−xLu0.575+x)F2.15+2x single crystals

✍ Scribed by Yuki Furuya; Hidehiko Tanaka; Kentaro Fukuda; Noriaki Kawaguchi; Yuui Yokota; Takayuki Yanagida; Valery Chani; Akira Yoshikawa

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 885 KB
• Volume: 318
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2010.10.037

✦ Synopsis

a b s t r a c t (Na 0.425 À x Lu 0.575 + x À y Eu y )F 2.15 + 2x (x ¼ 0, 70.05, y ¼ 0.001, 0.01, 0.05) single crystals were grown from the melt by the precise atmosphere control type micro-pulling-down (m-PD) method. The grown crystals were single-phase materials that were confirmed by X-ray diffraction, and their lattice constants increased when substitution of Lu with Eu increased. The crystals demonstrated about 90% transmittance in the 400-900 nm region that decreased with greater doping with Eu or Na. In all the crystals, strong absorption resulted from Eu 2 + 5d-4f transition was observed around 200-350 nm. Eu 2 + 5d-4f photoluminescence and radioluminescence under a-ray excitation were also detected. The crystals with low content of Eu or Na had high photoluminescence intensity; however, the radioluminescence intensity was extremely low. Intensity of the Eu 3 + 4f-4f emission increased with increase in Eu concentration. Formation of Eu 2 + in the grown crystals was also detected especially in those that had low content of Eu and Na.