Radiative lifetime of free excitons in quantum wells

Andreani, Lucio Claudio; Tassone, F.; Bassani, F.

doi:10.1016/0038-1098(91)90761-j

Cited by 518 publications

(307 citation statements)

References 17 publications

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“…The optical decay rate opt (T 0 ,T ) includes the fact that only excitons in the low-energy, optically active states may emit light. [33][34][35] The optical decay rate also includes the fact that the indirect excitons in a GaAs CQW may have four spin projections on the z direction J z = −2, − 1, + 1, + 2; the states J z = ±1 emit light, whereas the states J z = ±2 are dark. 54 The splitting between the J z = ±1 and J z = ±2 states in the studied structure is small, 43,55,56 smaller than the thermal energy for the temperatures studied in this work; therefore we approximate the distribution of indirect excitons between the J z = ±1 and J z = ±2 states as even.…”

Section: B Simulationsmentioning

confidence: 99%

“…The inner ring occurs due to the heating of the exciton gas by laser excitation. The heating results in a reduction in the occupation of the low-energy optically active exciton states [33][34][35] and, in turn, the exciton emission intensity. When excitons travel away from the excitation spot they thermalize to the lattice temperature so that the emission intensity increases outside of the excitation spot forming the inner ring.…”

Section: Introductionmentioning

confidence: 99%

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Pattern formation in the exciton inner ring

et al. 2013

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We report on the two-beam study of indirect excitons in the inner ring in the exciton emission pattern. One laser beam generates the inner ring and a second weaker beam is positioned in the inner ring. The beam positioned in the inner ring is found to locally suppress the exciton emission intensity. We also report on the inner ring fragmentation and formation of multiple rings in the inner ring region. These features are found to originate from a weak spatial modulation of the excitation beam intensity in the inner ring region. The modulation of exciton emission intensity anticorrelates with the modulation of the laser excitation intensity. The three phenomena-inner ring fragmentation, formation of multiple rings in the inner ring region, and emission suppression by a weak laser beam in the inner ring-have a common feature: a reduction of exciton emission intensity in the region of enhanced laser excitation. This effect is explained in terms of exciton transport and thermalization.

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Section: B Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pattern formation in the exciton inner ring

et al. 2013

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“…In a single quantum well an exciton has a lifetime on the order of tens of picoseconds [Feldmann et al, 1987;Andreani et al, 1991;Deveaud et al, 1991].…”

Section: Single Quantum Wellmentioning

confidence: 99%

“…Indirect excitons considered in this dissertation have lifetimes on the order of tens of nanoseconds compared to direct excitons with lifetimes on the order of tens of picoseconds [Feldmann et al, 1987;Andreani et al, 1991;Deveaud et al, 1991;Butov et al, 1999a;.…”

Section: Long Lifetimementioning

confidence: 99%

Exciton Transport Phenomena in GaAs Coupled Quantum Wells

Leonard¹

2018

Springer Theses

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“…Radiative recombination of excitons in two-dimensional systems has been studied by a number of authors [15][16][17][18]. In a three-dimensional system, the linear coupling of photon and exciton mixes them into two branches of combined excitations, called polaritons [19], which can propagate unimpeded throughout the crystal.…”

Section: Distinction Features Of Reduced Dimensionalitymentioning

confidence: 99%

Optical Processes in Quantum Wells

Sham

1995

Acta Phys. Pol. A

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A review is given of the theoretical framework of exciton dynamics in quantum wells including the spin degrees of freedom. A study is made of various momentum, energy, and spin relaxation mechanisms including the effects of exciton-phonon interaction, the single-particle spin-flips by means of spin-orbit interaction and the exciton spin-ffip by means of the exchange interaction. All these competing mechanisms are taken into account in a set of equations governing the time evolution of the exciton spin populations. Solutions are then used to interpret observed time-resolved observations of polarized luminescence spectra. For excitons in a two-dimensional system such as a semiconductor quantum well, the breaking of the translational symmetry in the direction normal to the interface plane has been shown theoretically by Hanamura, by Andreani and Bassani, and by Citrin to result in a reckbination rate much faster than in a three-dimensional system. Yet, experiments show ckparable decay rates in two-and three-dimensional excitons. Recent experiments with high time resolutions show two decay times for the total luminescence intensity. The slower one agrees witl the one usually observed and interpreted as the radiative recombination time. We shall give an explanation for the fast decay as a ckbination of radiative recombination and single-particle spin-flip and for the slow decay as the radiative recombination slowed down by the presence of lower energy dark states for excitons with parallel spins. The ability to use the same theory to account for the polarization behavior confirms the importance of the exciton spin dynamics. Furthermore, the longitudinal electric field dependence is used to check our theory of exchange.

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Radiative lifetime of free excitons in quantum wells

Cited by 518 publications

References 17 publications

Pattern formation in the exciton inner ring

Pattern formation in the exciton inner ring

Exciton Transport Phenomena in GaAs Coupled Quantum Wells

Optical Processes in Quantum Wells

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