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Experimental and theoretical studies of polaron optical properties in KNbO3 perovskite |
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| Authors: | L Grigorjeva V Pankratov RI Eglitis EA Kotomin G Borstel |
| Institution: | a Institute of Solid State Physics, University of Latvia, Kengaraga str. 8, Riga LV-1063, Latvia b Wake Forest University, Winston-Salem, NC 27109, USA c Dept. of Physics, Universität Osnabrück, Fachbereich Physik, Barbarastrase 7, D-49069 Osnabrück, Germany d Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany |
| Abstract: | Time-resolved absorption and luminescence spectra have been measured in KNbO3 perovskite crystals after pulsed band-gap excitation by 200 fs laser pulses and 10 ns electron pulses. Quantum chemical calculations using the large unit cell periodic model support the interpretation of the observed transient absorption bands at 0.8 and 1.1 eV as the self-trapped electron polarons and bound hole polarons, respectively. The activation energy for the 2.2 eV green luminescence quenching is 0.05 eV. We suggest that the short lifetime (<15 ns) of the luminescence at RT is caused by the radiative recombination of nearest electron and hole polarons. |
| Keywords: | 71 15 Ap 71 35 Cc 71 38 Ht |
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