Kinetics of light-induced polaron- and VIS-centers in SBN:Ce single crystals at low temperature
Autor(en): | Gubaev, A. Kapphan, S. Kislova, I. Kutsenko, A. Pankrath, R. Vikhnin, V. |
Stichwörter: | Absorption spectroscopy; Cerium compounds; Charge transfer; Excitons; Photorefractive materials; Polarons; Semiconductor doping; Semiconductor lasers, Bipolarons; Charge transfer vibronic exitons (CTVE); Light-induced polarons; Polaron absorptions, Single crystals | Erscheinungsdatum: | 2005 | Journal: | Physica Status Solidi C: Conferences | Volumen: | 2 | Ausgabe: | 1 | Startseite: | 167 | Seitenende: | 170 | Zusammenfassung: | The promising photorefractive crystal SrxBa1-xNb 2O6 (SBN, congruent composition x=0.61) can be doped with polyvalent ions like Ce to enhance photorefractive properties. Illumination with blue Ar+-laser light at low temperature creates light-induced NIR and VIS absorption bands. The NIR absorption has been identified as being due to Nb4+ electron polarons and their properties have been investigated in some detail. The VIS-Centers are less well understood and their nature is still under discussion. It has been shown by our previous measurements that illumination with red Kr+-laser light (647 nm) or red laser diodes (673 nm) leads to a dissociation of the VIS-Centers and a simultaneous build-up of a transient NIR-polaron absorption. We report here some new facts important for the simplified charge transfer model needed to describe quantitatively the equilibrium values and the dynamics of the NIR-polaron and VIS-center absorption. These features give new insight into the dynamic nature of these VIS-centers, which are currently being discussed as either bipolarons (in analogy to LiNbO3) or polarons trapped at charged centers, or charge transfer vibronic exitons (CTVEs) being trapped at charged centers. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
ISSN: | 16101634 | DOI: | 10.1002/pssc.200460137 | Externe URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-27344453356&doi=10.1002%2fpssc.200460137&partnerID=40&md5=49cbfce70f00c7976b34d52518e0f47a |
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geprüft am 20.05.2024