Photoluminescence lifetime distributions of chalcogenide glasses obtained by wide-band frequency resolved spectroscopy

Photo luminescence (PL) lifetime distributions for amorphous arsenic chalcogenides g-As2Se3 and g-As2S3, and amorphous selenium a-Se, are obtained for the first time using a quadrature frequency resolved spectroscopy (QFRS) technique modified for nanosecond resolution. The g-As2S3 and a-Se chalcogenides exhibit double-peak lifetime distributions, whereas the lifetime distribution of g-As2Se3 peaks uniquely at around 10(-4) s, which is consistent with earlier results. PL fatigue is found to reduce the intensity of PL but not affect the observed PL lifetimes. A self-trapped exciton model is adopted to explain the experimental results, providing reasonable mechanisms for the two-component lifetimes and associated phenomena. For a-Se, singlet-triplet exchange energy of approximate to160 meV is estimated. (C) 2003 Elsevier B.V. All rights reserved.