TY  - JOUR
AU  - Zorenko, T.
AU  - Gorbenko, V.
AU  - Witkiewicz, S.
AU  - Zorenko, Yu
TI  - Study of the luminescence of Eu<sup>2+</sup> and Eu<sup>3+</sup> states in Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub>:Eu garnet using synchrotron radiation excitation
JO  - Optical materials
VL  - 99
SN  - 0925-3467
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PUBDB-2020-02819
SP  - 1-4
PY  - 2020
AB  - The work is dedicated to the investigation of Eu<sup>2+</sup> and Eu<sup>3+</sup> luminescence centers in the Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub> garnet using synchrotron radiation excitation. The luminescence of Eu<sup>2+</sup> and Eu<sup>3+</sup> states was observed in the emission spectra of Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub>:Eu ceramics under excitation with energies in the exciton range and the range above band gap of this garnet. The luminescence of Eu<sup>2+</sup> ions Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub> host is observed in the band peaked at 450–460 nm with decay time in the ten ns range and excited in the two wide bands peaked at 5.04 and 6.05 eV, related to the allowed 4f-5d transitions of Eu<sup>2+</sup> ions. The Eu<sup>3+</sup> luminescence can be excited via the Eu<sup>2+</sup> luminescence. We have also found the energies of formation of excitons bound with Eu<sup>2+</sup> and Eu<sup>3+</sup> ions in Ca3Ga2Ge3O12, being equal to 7.64 and 6.95 eV, respectively, and the onset of interband transitions in this garnet which is equal to 7.83 eV at 8 K. Strong increase of the luminescence intensity of Eu<sup>2+</sup> and Eu<sup>3+</sup> centers is observed under excitation above 21 eV due to multiplication of electronic excitation in Ca<sub>3</sub>Ga<sub>2</sub>Ge<sub>3</sub>O<sub>12</sub> host. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000518692000081
DO  - DOI:10.1016/j.optmat.2019.109498
UR  - https://bib-pubdb1.desy.de/record/441951
ER  -