Effect of electron and hole accumulation on magneto-optical spectra of an undoped GaAs/GaxAl1−xAs quantum well
| Autor: | S. R. Andrews, T.M. Kerr, R. T. Harley, Annette S. Plaut |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | Physical Review B. 42:1332-1338 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.42.1332 |
| Popis: | We have performed magnetophotoluminescence and magnetophotoluminescence-excitation spectroscopy at 1.8 K on a GaAs/${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{Al}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As quantum-well structure in which the carrier density in a single 50 \AA{} quantum well can be varied from zero up to about 2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ carriers ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ by use of a Schottky gate. This results from transfer of either electrons or holes photoexcited in thicker GaAs layers in the structure and thereby allows the investigation of carrier-density-dependent effects in a single sample. The data for the empty well are consistent with previous studies of magneto-optics of atomic excitons. With a Fermi sea of heavy holes or electrons present, the spectra show evidence of band-gap renormalization and phase-space filling. Also the lowest inter-Landau-level transition was observed to follow a linear field dependence for fields lower than filling factor \ensuremath{\nu}=2 but to have a particularly weak magnetic field dependence at higher fields. This is consistent with crossover from free carrier to excitonic behavior at \ensuremath{\nu}=2 and is compared to recent theoretical calculations. |
| Databáze: | OpenAIRE |
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