Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 12: Poster I
HL 12.24: Poster
Montag, 8. März 2004, 16:30–19:00, Poster A
Emission stimulation in opals — •Sergei Romanov1, Dmitry Chigrin1, Clivia Sotomayor Torres1, Nikolai Gaponik2, Alexander Eychmueller2 und Andrei Rogach3 — 1Inst. of Materials Science and Dept. of Electrical and Information Engineering, University of Wuppertal, 42097, Germany — 2Inst. of Physical Chemistry, University of Hamburg, 20146, Germany — 3Dept. of Physics, University of Munich, 80799, Germany
Light sources in photonic crystals (PhCs) attract considerable attention owing to improvement of emitter parameters. We studied the ballistic emission of CdTe nanocrystals, which were layer-by-layer embedded in thin opal films, near the Bragg PBG as a function of excitation power and angle of detection. Two-parameter exponential fit to the emission intensity vs. excitation power curve was used to extract the power radiated by saturated emitter and the saturation threshold. In the PBG the spectrum of the former shows a minimum in contrast to the maximum of the latter. The decrease of the saturated emission power was associated with the suppression of the spontaneous emission rate in a given optical mode and the increase the saturation threshold - as the acceleration of the radiative recombination.
We argue that photons emitted along the bandgap direction are coupled to highly inhomogeneous PhC eigenmodes propagating with low group velocity. This imposes resonator conditions and the backreaction of the radiation to emitters stimulates the radiative recombination.