Magnetooptical investigations of single self assembled In0.3Ga0.7As quantum dots

Mensing, T.; Reitzenstein, S.; Löffler, Andreas; Reithmaier, Johann Peter; Forchel, A.

doi:10.1016/j.physe.2005.12.024

Cited by 4 publications

(4 citation statements)

References 13 publications

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Section: Candidate Semiconductor Systemssupporting

confidence: 81%

“…As this is a simple model, these values are consistent with those of localised states in QDs. Electron microscopy of a QD system with similar composition shows the QDs are of length 40-100nm and width 20-30nm; these states have similar diamagnetic shifts to those measured in the present work [11]. µPL emission maps at six photon energies are shown in Figure 4 for a 15µm × 15µm region indicating elongation of the emitting regions in the [110] direction.…”

Section: Candidate Semiconductor Systemssupporting

confidence: 76%

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Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

Piper¹,

Eastham²,

Ediger³

et al. 2010

J. Phys.: Conf. Ser.

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We review the practical conditions required to achieve a non-equilibrium BEC driven by quantum dynamics in a system comprising a microcavity field mode and a distribution of localised two-level systems driven to a step-like population inversion profile. A candidate system based on eight 3.8nm layers of In0.23Ga0.77As in GaAs shows promising characteristics with regard to the total dipole strength which can be coupled to the field mode.

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Section: Candidate Semiconductor Systemssupporting

confidence: 81%

Section: Candidate Semiconductor Systemssupporting

confidence: 76%

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

Piper¹,

Eastham²,

Ediger³

et al. 2010

J. Phys.: Conf. Ser.

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“…Therefore, a different approach for identifying such a two-stage character of the localizing potential in QDash structures is highly desired. Such a method can be based on the fact that the anisotropy of the confinement is reflected in the polarization properties of the luminescence [17][18][19][20][21][22] . This relation can be traced back to subband mixing effects: Oppositely circularly polarized contributions to the optical emission originating from heavy and light hole transitions interfere, leading to elliptically polarized emission and to the appearance of the preferential orientation of the linear polarization 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Carrier trapping and luminescence polarization in quantum dashes

et al. 2012

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We study experimentally and theoretically polarization-dependent luminescence from an ensemble of quantum-dot-like nanostructures with a very large in-plane shape anisotropy (quantum dashes). We show that the measured degree of linear polarization of the emitted light increases with the excitation power and changes with temperature in a non-trivial way, depending on the excitation conditions. Using an approximate model based on the k.p theory, we are able to relate this degree of polarization to the amount of light hole admixture in the exciton states which, in turn, depends on the symmetry of the envelope wave function. Agreement between the measured properties and theory is reached under assumption that the ground exciton state in a quantum dash is trapped in a confinement fluctuation within the structure and thus localized in a much smaller volume of much lower asymmetry than the entire nanostructure.Comment: 13 pages, 9 figures; considerably extended, additional discussion and new figures include

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“…, where e = α or h denotes an electron or a hole, and * α m is the effective mass of the electron or hole, and α  is the lateral expansion of the carrier's wavefunction perpendicular to the magnetic field [44]. For self-assembled QDs grown by using molecular beam epitaxy, the diamagnetic coefficient γ is approximately 5-10 μeV/T 2 for strongly confined QDs [14,39,40,44], and up to 32.8 μeV/T 2 for large elongated QDs [45]. Figure 4 shows the diamagnetic coefficients of all the resolved PL peaks with different excitonic energies.…”

mentioning

confidence: 99%

Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

et al. 2015

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We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. This effect can be attributed to the expansion of the wavefunction of remaining electrons in the wetting layer or the spread of electrons in the excited states of the quantum dot to the wetting layer after recombination. In this case, the wavefunction extent of the final states in the quantum dot plane is much larger than that of the initial states because of the absence of holes in the quantum dot to attract electrons. The properties of emitted photons that depend on the large electron wavefunction extents in the wetting layer indicate that the coupling occurs between systems of different dimensionality,which is also verified from the results obtained by applying a magnetic field in different configurations. This study paves a new way to observe hybrid states with zero-and two-Nano Res. dimensional structures, which could be useful for investigating the Kondo physics and implementing spin-based solid-state quantum information processing.Semiconductor quantum dots (QDs), also known as "artificial atoms", have attracted considerable interest because of their application to quantum optoelectronic devices such as singlephoton sources [1-6], quantum bits [7,8], quantum logic gates [9], and photon-spin interfaces [10][11][12]. Owing to the quasi-zero-dimensional nature of QDs, many-body effect induced exciton states have been achieved in single QDs by controlling charge states with external electric and magnetic fields [13][14][15]. Following the discovery of graphene [16], two-dimensional materials, such as MoS2 [17, 18] and black phosphorous [19], have been investigated extensively. Recently, the coupling between QDs and two-dimensional extended states has been investigated to demonstrate the Kondo physics [15,[20][21][22][23][24] and Fano effect [25,26]. Hybridization between a single QD and a twodimensional continuum state has been studied experimentally and theoretically in various systems [21,[27][28][29][30][31][32]. For self-assembled QDs grown by molecular beam epitaxy (known as Stranski-Krastanov growth), a wetting layer with a thickness of a few monolayers is always formed underneath the QDs [33][34][35], which naturally provides a platform for the formation of coupled systems for many-body exciton states [15,27]. Karrai et al. [27] have shown the coherent hybridization of localized QD states and extended continuum states in the wetting la...

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Magnetooptical investigations of single self assembled In0.3Ga0.7As quantum dots

Cited by 4 publications

References 13 publications

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

Carrier trapping and luminescence polarization in quantum dashes

Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects

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