Visualizing cation vacancies in Ce:Gd3Al2Ga3O12scintillators by gamma-ray-induced positron annihilation lifetime spectroscopy

Kosuke Fujimori, Mamoru Kitaura, Yoshitaka Taira, Masaki Fujimoto, Heishun Zen, Shinta Watanabe, Kei Kamada, Yasuaki Okano, Masahiro Katoh, Masahito Hosaka, Jun Ichiro Yamazaki, Tetsuy Hirade, Yoshinori Kobayashi, Akimasa Ohnishi

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1 Citation (Scopus)

Abstract

To clarify the existence of cation vacancies in Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillators, we performed gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS). GiPALS spectra of GAGG and Ce:GAGG comprised two exponential decay components due to positron annihilation at bulk and defect states. By an analogy with Ce:Y3Al5O12, the defect-related component was attributed to Al/Ga-O divacancy complexes. This component was weaker for Ce,Mg:GAGG, which correlated with the suppression of electron traps responsible for phosphorescence. O vacancies were charge compensators for Al/Ga vacancies. The lifetime of the defect-related component was changed by Mg co-doping. This was explained by the formation of vacancy clusters.

Original languageEnglish
Article number085505
JournalApplied Physics Express
Volume13
Issue number8
DOIs
Publication statusPublished - 2020 Aug 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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