Behavior of the Fermi-edge singularity in the photoluminescence spectra of a high-density two-dimensional electron gas

H. Kissel, U. Zeimer, A. Maaßdorf, and M. Weyers
Ferdinand-Braun-Institut für Höchstfrequenztechnik, Albert-Einstein-Straße 11, D-12489 Berlin, Germany

R. Heitz, and D. Bimberg
Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany

Yu.I. Mazur, G.G. Tarasov, Vas.P. Kunets, U. Müller, Z.Ya. Zhuchenko, and W.T. Masselink
Institut für Physik, Humboldt-Universität zu Berlin, Invalidenstr. 110, D-10115 Berlin, Germany

Published in:
Physical Review B, Vol. 65 (2002).
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Abstract:
Fundamentally different behavior of the Fermi-edge singularity (FES) in photoluminescence of heavily doped pseudomorphic modulation-doped Al_xGa_1-x/In_yGa_1-y/GaAs heterostructures is observed. The noteworthy features are: (i) the FES enhancement from E_F of n=1 electronic subband is observed under condition of the n=2 subband population, (ii) the heavy-hole localization energy is directly observed in the FES development, (iii) the magnitude of the FES increases with increasing temperature at low temperatures, and (iv) the FES is a nonmonotonic function of the excitation density. A qualitative analysis is performed in terms of heavy-hole localization by potential fluctuations in the In_yGa_1-yAs quantum well.

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