Energy Levels of ${\hbox {Ce}}^{3+}$ in ${\hbox {Lu}}_{0.8}{\hbox {Sc}}_{0.2}{\hbox {BO}}_{3}$ Host: A Comparison Study Between X-Ray Photoelectron Spectroscopy and Pure Optical Method

Cerium doped lutetium scandium orthoborate
${\hbox {Ce}}^{3+}{\hbox {:Lu}}_{0.8}{\hbox {Sc}}_{0.2}{\hbox {BO}}_{3}$
is a novel and promising inorganic scintillator. For the sake of better understanding its scintillation mechanism, several approaches were undertaken to locate the
${\hbox {Ce}}^{3+}$
energy levels relative to the host. To estimate the energy position of
${\hbox {Ce}}^{3+}4f$
levels with respect to the valence band, X-ray photoelectron spectroscopy (XPS) was used. Furthermore, the photoluminescence decays as a function of temperature, a widely used technique, was utilized to find the relative positions of
${\hbox {Ce}}^{3+}5d$
levels to the conduction band. Finally, the
${\hbox {Ce}}^{3+}$
energy levels in
${\hbox {Lu}}_{0.8}{\hbox {Sc}}_{0.2}{\hbox {BO}}_{3}$
host was constructed, meanwhile, the effectiveness of the XPS technique to estimate the energy position of
${\hbox {Ce}}^{3+}$
4f levels relative to the conduction band was evaluated.