Quantum-size effects on radiative lifetimes and relaxation of excitons in semiconductor nanostructures

Bellessa, J.; Voliotis, Valia; Grousson, R.; Wang, X. L.; Ogura, Mutsuo; Matsuhata, Hirofumi

doi:10.1103/physrevb.58.9933

Cited by 126 publications

(86 citation statements)

References 54 publications

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“…The decay time of localized excitons is inversely proportional to the coherence volume of the exciton, 15) which in the present case is given by the volume of the localization centre. 16) Consequently, as the QW thickness is constant across the sample, we attribute the variation in loc to local change in the spatial extension of exciton localization centres.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, since we do not observe any change in QW emission linewidth when scanning across a sample of given QW thickness, we assume that E loc is constant along the QW plane. Regarding loc , it only depends on the coherence volume of the localized exciton 15,16) and we take it to be constant with temperature. In contrast, r depends on M and on the oscillator strength f osc , and increases linearly with temperature, due to the population of states lying out of the light cone (i.e., exciton states that do not couple to light).…”

Section: Resultsmentioning

confidence: 99%

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Temperature-Dependence of Exciton Radiative Recombination in (Al,Ga)N/GaN Quantum Wells Grown on a-Plane GaN Substrates

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Teisseyre

Suski

et al. 2013

Jpn. J. Appl. Phys.

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This article presents the dynamics of excitons in a-plane (Al,Ga)N/GaN single quantum wells of various thicknesses grown on bulk GaN substrates. For all quantum well samples, recombination is observed to be predominantly radiative in the low-temperature range. At higher temperatures, the escape of charge carriers from the quantum well to the (Al,Ga)N barriers is accompanied by a reduction in internal quantum efficiency. Based on the temperature-dependence of time-resolved photoluminescence experiments, we also show how the local disorder affects the exciton radiative lifetime at low temperature and the exciton non-radiative lifetime at high temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Temperature-Dependence of Exciton Radiative Recombination in (Al,Ga)N/GaN Quantum Wells Grown on a-Plane GaN Substrates

Corfdir

Teisseyre

Suski

et al. 2013

Jpn. J. Appl. Phys.

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“…For larger QDs, i.e., in the weak confinement regime, the exciton lifetime is known to be inversely proportional to the QD volume. 26 Indeed, in this case substituting Eq. (4) into Eq.…”

Section: ͑4͒mentioning

confidence: 99%

Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

2004

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“…Spin relaxation would remain an issue, but a recent experimental result shows that the 1X spin decoherence time T 2 can be much longer than the radiative lifetime in CdSe quantum dots [19]. Alternatively, one could reduce τ rad , either by using larger quantum dots [28], or by placing the 1X state on resonance with a microcavity [29]. It has already been demonstrated that the spontaneous emission rates of quantum dots can be enhanced by a factor of up to 5 in pillar microcavities [30].…”

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confidence: 99%

Polarization-correlated photon pairs from a single quantum dot

et al. 2002

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Polarization correlation in a linear basis, but not entanglement, is observed between the biexciton and single-exciton photons emitted by a single InAs quantum dot in a two-photon cascade. The results are well described quantitatively by a probabilistic model that includes two decay paths for a biexciton through a non-degenerate pair of one-exciton states, with the polarization of the emitted photons depending on the decay path. The results show that spin non-degeneracy due to quantumdot asymmetry is a significant obstacle to the realization of an entangled-photon generation device. [4,5,6], but they can also generate sequences of photons in a radiative cascade [7,8]. In such a cascade, each photon has a unique wavelength, and the photons may also have correlated, or even entangled [9] polarizations.In the two-photon cascade, a biexciton singlet state (two electrons and two holes, 2X) decays to one of two optically active single-exciton states (one electron and one hole, 1X) by emitting one photon, and then to the empty-dot state by emitting a second photon. In theory, the polarization properties of photon pairs emitted through these two decay paths result entirely from properties of the optically-active 1X doublet [10,11,12]. For a symmetric quantum dot, the two 1X states are degenerate, and the two decay paths become "indistinguishable," ideally producing polarization-entangled photons [9]. For an asymmetric quantum dot, the 1X doublet is split through the electron-hole exchange interaction into states that couple to photons having orthogonal linear polarizations [13,14,15]. If this splitting is much larger than the radiative linewidth, then the two paths become "distinguishable," with one decay path producing two horizontally-polarized photons and the other producing two vertically polarized photons, for example. In this case, polarization correlation is expected only in a single, preferred basis. Some additional factors are also important, such as spin flip [16] and decoherence processes [17,18,19] that randomize the intermediate 1X state, and valence-band mixing [20].In this article, we present an experimental study of the polarization correlation properties of photon pairs emitted through biexciton decay in a single InAs quantum dot. While temporal correlations between 1X and 2X photons have previously been seen [21], polarization correlation has not yet been reported, to our knowledge, although a lack of such correlation has been mentioned elsewhere [22]. For our sample, we observe a strong polarization correlation in a linear polarization basis, verifying the theoretical picture described above. However, we do not observe entanglement, suggesting that quantum-dot asymmetry is an obstacle to realizing an entangled photon source.A sample was fabricated containing self-assembled InAs quantum dots [3] grown by molecular-beam epitaxy on a (001) GaAs substrate, capped by 75 nm of GaAs. A high growth temperature increased intermixing between the InAs and surrounding GaAs, shortening the quantum-dot emission wa...

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Quantum-size effects on radiative lifetimes and relaxation of excitons in semiconductor nanostructures

Cited by 126 publications

References 54 publications

Temperature-Dependence of Exciton Radiative Recombination in (Al,Ga)N/GaN Quantum Wells Grown on a-Plane GaN Substrates

Temperature-Dependence of Exciton Radiative Recombination in (Al,Ga)N/GaN Quantum Wells Grown on a-Plane GaN Substrates

Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

Polarization-correlated photon pairs from a single quantum dot

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