Evidence for two-path recombination of photoinduced small polarons in reduced LiNbO(3).
The recombination of photoinduced free Nb(4+)(Nb) and bound Nb(4+)(Li) small polarons toNb(4+)(Li): Nb(4+)(Nb) bipolarons is investigated in nominally pure, reduced LiNbO(3) single crystals by means of excited-state-absorption spectroscopy. We discovered a two-component decay of the light-induced absorption alpha(li)(t) for probe light at lambda=785 nm and moderate pump beam intensities (I(p) << 670 GW/m(2)). These experimental results give strong evidence for the existence of a two-path recombination of the photoinduced polarons. A corresponding model taking into account hopping charge transport and trapping is presented.
Merschjann
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Fachbereich Physik, Universität Osnabrück, D-49069 Osnabrück, Germany.
Berben
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Imlau
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Wöhlecke
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