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HL: Halbleiterphysik

HL 49: Poster II

HL 49.73: Poster

Thursday, March 27, 2003, 16:30–19:00, HSZ/P2

Non-Lorentzian lineshapes in the emission spectra of single self-assembled CdSe/ZnSe quantum dots — •Brian Patton, Wolfgang Langbein, and Ulrike Woggon — Experimentelle Physik IIb, Universität Dortmund, Otto-Hahn-Straße 4, 44221 Dortmund

We present an analysis of the emission lineshape of single exciton and charged exciton (trion) states in a CdSe/ZnSe quantum-dot system. In a set of optical experiments we photo-excited carriers in the barrier and studied the single quantum dot emission at different temperatures, excitation intensities and polarisations. We have observed a non-Lorentzian lineshape comprising of two components; a broad, phonon-assisted band and a sharp zero-phonon line. As the temperature increases we see that the phonon-assisted component contributes more strongly to the spectrally-integrated intensity of the line. We present a model for the acoustic-phonon assisted recombination of both trion and exciton states which includes the effect of single-phonon emission or absorption. The results of this analysis give an upper limit to the Lorentzian component of the zero-phonon line of approximately 100 µeV at 10K.