Crystal Growth and Characterization of Rare Earth Doped ${\hbox{K}}_{3}{\hbox{LuF}}_{6}$

Transparent K
₃
LuF
₆
single crystals doped with rare earth ions were successfully grown by the micro-pulling down method (μ-PD). X-ray diffraction measurements showed that the as-grown crystals possess monoclinic structure with P2
₁
/n space group. The radio- and photoluminescence spectra of the grown crystals were measured in the vacuum ultraviolet (VUV) and ultraviolet (UV) region. The intrinsic luminescence of K
₃
LuF
₆
was observed at 163 and 200 nm. Nd-doped crystals displayed, in contrast, emission at 183 nm, due to the Nd
³⁺
5d-4f transition, and their radioluminescence intensity increases with increasing Nd concentration. Tm:K
₃
LuF
₆
showed high emission intensity at 190 nm in the radio- and photoluminescence spectra (λ
_exc
= 155 nm). Moreover, the emission intensity of 0.5%Tm:K
₃
LuF
₆
was higher than that of 5%Tm:K
₃
LuF
₆
. Concerning Er:K
₃
LuF
₆
, the emission at 165 nm was detected for the 0.5%Er:K
₃
LuF
₆
.