11 May 1994 Observation of the Mahan exciton using electroreflectance spectroscopy of a quantum well structure
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Proceedings Volume 2139, Quantum Well and Superlattice Physics V; (1994) https://doi.org/10.1117/12.175697
Event: OE/LASE '94, 1994, Los Angeles, CA, United States
Abstract
We report on the influence of a 2-D electron gas (2-D EG) on the electroreflectance (ER) spectra of an AlGaAs/GaAs/AlGaAs single quantum well. The ER and, for comparison, photoluminescence (PL) measurements were performed as a function of temperature and carrier density in a gated 2-D EG. For negative gate voltages the observed ER signals are due to the quantum confined Stark effect (QCSE). For forward biases and at a temperature of 10 K, the broadening of the PL line and the increase of the Stokes shift between the corresponding ER and PL transitions give clear evidence for the population of the first electron subband. Moreover, with the formation of the 2-D EG we found a strong enhancement of the magnitude as well as two additional phase inversions for the ER transitions between the ground heavy and light hole states and the first electron subband. These effects were seen to decrease with increasing temperature. The results are explained in terms of transformation of the excitonic absorption mechanism from a QCSE-related mechanism to one determined by the `Mahan exciton.'
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Rudiger Goldhahn, Gerhard Gobsch, S. Shokhovets, J. Martyn Chamberlain, Tin S. Cheng, Mohamed Henini, "Observation of the Mahan exciton using electroreflectance spectroscopy of a quantum well structure", Proc. SPIE 2139, Quantum Well and Superlattice Physics V, (11 May 1994); doi: 10.1117/12.175697; https://doi.org/10.1117/12.175697
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