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Published on: November 2, 2013
Bound states in optical absorption of semiconductor quantum wells containing a two-dimensional electron Gas
Huard1, Cox, Saminadayar
1CEA-Grenoble, Departement de Recherche Fondamentale sur la Matiere Condensee, 17 avenue des Martyrs, 38054 Grenoble Cedex 9, France.
Abstract:
The dependence of the optical absorption spectrum of a semiconductor quantum well on two-dimensional electron concentration n(e) is studied using CdTe samples. The trion peak (X-) seen at low n(e) evolves smoothly into the Fermi edge singularity at high n(e). The exciton peak (X) moves off to high energy, weakens, and disappears. The X,X- splitting is linear in n(e) and closely equal to the Fermi energy plus the trion binding energy. For Cd0.998Mn0.002Te quantum wells in a magnetic field, the X,X- splitting reflects unequal Fermi energies for M = +/-1/2 electrons. The data are explained by Hawrylak's theory of the many-body optical response including spin effects.
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