Premium
Trap Levels in Eu‐Doped SrAl 2 O 4 Phosphor Crystals Co‐Doped with Rare‐Earth Elements
Author(s) -
Katsumata T.,
Toyomane S.,
Sakai R.,
Komuro S.,
Morikawa T.
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00856.x
Subject(s) - phosphor , phosphorescence , doping , activator (genetics) , photoluminescence , analytical chemistry (journal) , materials science , luminescence , persistent luminescence , emission spectrum , fluorescence , mineralogy , spectral line , chemistry , thermoluminescence , optics , optoelectronics , physics , biochemistry , chromatography , astronomy , gene
SrAl 2 O 4 :Eu 2+ phosphor crystals co‐doped with auxiliary activators such as La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or Y have been grown by the floating zone (FZ) technique. Photoluminescence spectrum (PL), time‐resolved PL, and thermally stimulated luminescence (TSL) are evaluated to clarify the long‐duration phosphorescence mechanism of SrAl 2 O 4 , Eu, and Ln phosphors. TSL spectra were measured in the temperature range from RT to 600 K to evaluate the depth and densities of the traps generated by the doping of auxiliary activators that are responsible for the long‐duration phosphorescence. The peak wavelength of PL does not vary with auxiliary activator elements, while decay curves vary greatly with the auxiliary activators. The trap depth and the densities of the trapped carriers estimated based on the hole trap model also vary with the auxiliary activator elements. The traps generated at around E =0.5 eV by the auxiliary activators, Nd, Dy, and Tm, with sufficient densities are effective for the long‐duration phosphorescence.