Инд. авторы:	Ogorodnikov I.N., Pustovarov V.A., Yakovlev S.A., Isaenko L.I.
Заглавие:	Spectroscopic study of red-light-emitting centers in K2Al 2B2O7: Fe single crystals
Библ. ссылка:	Ogorodnikov I.N., Pustovarov V.A., Yakovlev S.A., Isaenko L.I. Spectroscopic study of red-light-emitting centers in K2Al 2B2O7: Fe single crystals // Optical Materials. - 2013. - Vol.35. - Iss. 6. - P.1173-1178. - ISSN 0925-3467. - EISSN 1873-1252.
Внешние системы:	DOI: 10.1016/j.optmat.2013.01.009; SCOPUS: 2-s2.0-84875466600;
Реферат:	eng: We report on spectroscopic study of red-light-emitting centers in K 2Al2B2O7 (KABO) single crystals containing ca. 2 ppm of Fe3+. Owing to the low Fe3+- concentration, KABO does not show noticeable absorption due to Fe3+ d-d-transitions in the visible spectral region, but it exhibits the charge-transfer (CT) UV-absorption bands O-Fe at 4.7, 5.7 and 6.5 eV. The red photoluminescence at 1.675 eV (FWHM = 0.173 eV) is due to intracenter 4T1 (4G) → 6A1 (6S) transitions in Fe3+ ions. Because of partial overlapping of the fundamental absorption edge of the crystal, where mobile excitons are created, and a broad CT absorption band at 6.5 eV, the most intensive red emission occurs at 7 K upon excitation in the excitonic energy region. The presence of two nonequivalent Al2O7 clusters in KABO lattice provides two different types of red-light-emitting centers in the form of Fe3+ ion occupied the Al3+ tetrahedral site. Superposition of their luminescence bands determines both the spectrum and temperature dependence of red emission in KABO at T = 7-80 K: two bands with the ratio of intensities of ca. 2:1 are 20 meV-shifted relative to each other; two-stage thermal quenching obeys the Mott law with ET = 9 and 20 meV. © 2013 Elsevier B.V. All rights reserved.
Ключевые слова:	Aluminum; Temperature distribution; Spectroscopic analysis; Single crystals; Luminescence; Crystal impurities; Charge transfer; Visible spectral regions; Temperature dependence; Spectroscopic studies; Red photoluminescence; Optical spectra; KABO; Impurity defects; Fundamental absorption edge; Temperature dependence; Optical spectra; Luminescence; KABO; Impurity defects;
Издано:	2013
Физ. характеристика:	с.1173-1178