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Constantini, J.-M.*; Ogawa, Tatsuhiko; Gourier, D.*
Journal of Physics; Condensed Matter, 35(28), p.285701_1 - 285701_12, 2023/04
Times Cited Count：0 Percentile：0(Physics, Condensed Matter)A novel analysis of luminescence is presented on the basis of virtual photon spectra (VPS) produced by charged particles (electrons or ions) passing by luminescent species such as defects or impurities, in wide band-gap ionic-covalent solids. The electron-energy dependence of experimental luminescence spectra of sapphire (
-Al
O
) is discussed in relation to the computed VPS for the primary and secondary electrons. The experimental luminescence spectra of -AlO are also analyzed in this framework for protons and helium ions in the MeV energy range. The variations of stopping power are consistent with the variation of the number of emitted VPs. The decay of luminescence yield versus ion stopping power is discussed on the basis of the variation of the computed VPS, and ionization and excitation induced by primary ions and secondary electrons. This decay is accounted for by a decrease of the yield of low-energy secondary electrons with the subsequent VP emission.
Constantini, J.-M.*; Seo, P.*; Yasuda, Kazuhiro*; Bhuian, AKM S. I.*; Ogawa, Tatsuhiko; Gourier, D.*
Journal of Luminescence, 226, p.117379_1 - 117379_10, 2020/10
Times Cited Count：5 Percentile：42.02(Optics)Cathodo-luminescence is used for detection of lattice defects, in particular oxygen vacancies in ceramics induced by electrons. However, how oxygen vacancy production efficiency depends on sample temperature, incoming electron flux, and electron energy was not clear. In this study, oxygen vacancies were made in the specimens of CeO by irradiation of 400-1250 keV electrons and the cathodoluminescence from thus induced vacancies were observed by photo-fiber probe combined with CCD. As the result, the dependence of luminescence intensity on specimen temperature depends on the carrier trapping frequency and luminescence efficiency while luminescence center production/annihilation speed determines the dependency on the incoming electron flux. Moreover, radiation transport calculation conducted by the particle transport simulation code PHITS indicates that the number of electrons above the defect production threshold energy is vital to explain incoming electron energy dependence.
