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G. Livescu, D. A. B. Miller, D. S. Chemla,
M. Ramaswamy, T. Y. Chang, N. Sauer, A. C. Gossard, and J. H. English, "Free carrier
and many-body effects in absorption spectra of modulation-doped quantum wells," IEEE
J. Quantum Electron., 24, 1677-1689, (1988). The temperature-dependent
optical absorption and luminescence spectra of GaAs/AlGaAs and InGaAs/InAlAs n-doped
modulation-doped quantum wells is discussed with emphasis on the peak seen at the edge of
the absorption spectra of these samples. A many-body calculation of the electron-hole
correlation enhancement is presented, which identifies this peak with the Mahan
exciton-the result of the Coulomb interaction between the photoexcited hole in the valence
band and the sea of electrons in the conduction band. This calculation accounts for the
strong dependence of the absorption edge peak on both the temperature and carrier
concentration, in good qualitative agreement with experimental data and with previously
published results. The changes induced by the carriers on the subband structure through
self-consistent calculations are also analyzed, and it is concluded that in these
symmetric structures, the changes are small for achievable carrier densities
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