Charged excitons in ZnSe-based quantum wells

Астахов, Г. В.; Yakovlev, D. R.; Кочерешко, В. П.; Ossau, W.; Nürnberger, J.; Faschinger, W.; Landwehr, G.

doi:10.1103/physrevb.60.r8485

Cited by 89 publications

(100 citation statements)

References 20 publications

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“…Identification of the charged and neutral exciton lines is based on magneto-optical spectra (for details see Refs. 31,35). Both exciton and trion transitions are also observable in reflectivity spectra (solid lines in Fig.…”

Section: Optical Spectra At a Zero Magnetic Fieldmentioning

confidence: 88%

“…For QWs with a very dilute twodimensional electron gas (2DEG) where the electron concentration n e ≪ 1 πaB 2 (here a B is the radius of the quasi-two-dimensional exciton), a negatively charged exciton complex is the energetically lowest excitation [28,29,30,31]. The negatively charged exciton is composed of two electrons and a hole, and is commonly called a trion (T), and is analogous to the negatively charged H − state of the hydrogen atom.…”

Section: Introductionmentioning

confidence: 99%

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Magneto-optics of two-dimensional electron gases modified by strong Coulomb interactions in ZnSe quantum wells

et al. 2005

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The optical properties of two-dimensional electron gases in ZnSe/(Zn,Be)Se and ZnSe/(Zn,Be,Mg)Se modulation-doped quantum wells with electron densities up to 1.4 × 10 12 cm −2were studied by photoluminescence, photoluminescence excitation and reflectivity in a temperature range between 1.6 and 70 K and in external magnetic fields up to 48 T. In these structures, the Fermi energy of the two-dimensional electron gas falls in the range between the trion binding energy and the exciton binding energy. Optical spectra in this regime are shown to be strongly influenced by the Coulomb interaction between electrons and photoexcited holes. In high magnetic fields, when the filling factor of the two-dimensional electron gas becomes smaller than two, a change from Landau-level-like spectra to exciton-like spectra occurs. We attempt to provide a phenomenological description of the evolution of optical spectra for quantum wells with strong Coulomb interactions.

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Section: Optical Spectra At a Zero Magnetic Fieldmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Magneto-optics of two-dimensional electron gases modified by strong Coulomb interactions in ZnSe quantum wells

et al. 2005

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“…The negatively charged species T − are studied in detail in various material systems, such as GaAs/(Al,Ga)As, [3][4][5] CdTe-based, 6,7 and ZnSe-based [8][9][10] structures. Magnetooptical techniques play a key role in these investigations and allow one to obtain comprehensive information about the energy and the spin structure of the T − complex.…”

Section: Introductionmentioning

confidence: 99%

Positively versus negatively charged excitons: A high magnetic field study of CdTe/Cd1−xMgxTe quantum wells

et al. 2011

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A magneto-optical study of the energy and spin structure of charged excitons in a 20-nm-thick CdTe/Cd 0.65 Mg 0.35 Te quantum well is performed in strong magnetic fields up to 51 T. The type of resident carriers (holes or electrons) in the quantum well is controlled optically by above-barrier illumination, permitting a direct comparison of positively (T + ) versus negatively (T − ) charged excitons. The binding energies of the singlet states of these complexes behave qualitatively differently with increasing magnetic field B; namely, the binding energy decreases for T + and increases for T − with B. The triplet state of T + is identified in strong fields with a binding energy smaller than that of the T − triplet state.

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“…However, one of the striking differences of optical experiments, compared to transport, is the presence of photoexcited holes in the system, which can significantly influence its properties. In samples with very low carrier concentration, the Coulomb interaction between electrons and holes leads to the formation of negatively charged excitons, which have been a subject of intense research during the past decade (see, e.g., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]). For samples with relatively strong disorder, the commonly accepted picture is that at low density the two-dimensional electron system (2DES) breaks up into areas with finite density (electron puddles) and completely depleted regions, where neutral excitons (X 0 ) can form.…”

Section: Introductionmentioning

confidence: 99%

Charged Excitons in the Quantum Hall Regime

et al. 2004

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We review our recent optical experiments on two-dimensional electron systems at temperatures below 1 K and under high magnetic fields. The two-dimensional electron systems are realized in modulation-doped GaAsAlGaAs single quantum wells. Via gate electrodes the carrier density of the two-dimensional electron systems can be tuned in a quite broad range between about 1 × 10 10 cm −2 and 2 × 10 11 cm −2 . In dilute two-dimensional electron systems, at very low electron densities, we observe the formation of negatively charged excitons in photoluminescence experiments. In this contribution we report about the observation of a dark triplet exciton, which is observable at temperatures below 1 K and for electron filling factors < 1/3, i.e., in the fractional quantum Hall regime only. In experiments where we have increased the density of the two-dimensional electron systems so that a uniform two-dimensional electron system starts to form, we have found a strong energy anomaly of the charged excitons in the vicinity of filling factor 1/3. This anomaly was found to exist in a very narrow parameter range of the density and temperature, only. We propose a model where we assume that localized charged excitons and a uniform Laughlin liquid coexist. The localized charged exciton in close proximity to the Laughlin liquid leads to the creation of a fractionally-charged quasihole in the liquid, which can account for the experimentally observed anomaly.

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Charged excitons in ZnSe-based quantum wells

Cited by 89 publications

References 20 publications

Magneto-optics of two-dimensional electron gases modified by strong Coulomb interactions in ZnSe quantum wells

Magneto-optics of two-dimensional electron gases modified by strong Coulomb interactions in ZnSe quantum wells

Positively versus negatively charged excitons: A high magnetic field study of CdTe/Cd1−xMgxTe quantum wells

Charged Excitons in the Quantum Hall Regime

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