Luminescence and electronic excitations in KBe2BO3F2 crystals

Abstract

This paper reports on a study of the dynamics of electronic excitations in KBe 2BO 3F 2 (KBBF) crystals by low-temperature luminescent vacuum ultraviolet spectroscopy with nanosecond time resolution under photoexcitation by synchrotron radiation. The first data have been obtained on the kinetics of photoluminescence (PL) decay, time-resolved PL spectra, time-resolved PL excitation spectra, and reflection spectra at 7 K; the estimation has been performed for the band gap E g = 10. 6-11. 0 eV; the predominantly excitonic mechanism for PL excitation at 3. 88 eV has been identified; and defect luminescence bands at 3. 03 and 4. 30 eV have been revealed. The channels of generation and decay of electronic excitations in KBBF crystals have been discussed. © 2012 Pleiades Publishing, Ltd.