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Intrinsic Luminescence from Li 2 O Crystals Excited in the Exciton‐Band Region
Author(s) -
Itoh M.,
Murakami J.,
Ishii Y.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199905)213:1<243::aid-pssb243>3.0.co;2-1
Subject(s) - exciton , luminescence , photoluminescence , atomic physics , excitation , excited state , band gap , materials science , absorption band , impurity , radiative transfer , range (aeronautics) , molecular physics , chemistry , physics , condensed matter physics , optics , optoelectronics , organic chemistry , quantum mechanics , composite material
Photoluminescence of lithium oxide (Li 2 O) has been studied under the excitation with UV light in the fundamental absorption region at low temperatures. Two bands appear at 3.70 and 4.75 eV. The 3.70 and 4.75 eV bands are stimulated on the low‐ and high‐energy sides of the exciton reflection band peaking at 7.02 eV, respectively. An interesting fact is that there appears no luminescence under the above‐gap excitation. The 4.75 eV band is ascribed to radiative decay of self‐trapped excitons, and the 3.70 eV band is related to unavoidably existing defects or impurities. Both a broadening of the line width and a quenching of the intensity of the 4.75 eV band are also investigated in the temperature range 9 to 300 K. The present result is discussed in comparison with the theoretical model of the self‐trapped exciton in this material.