Excitonic effects in the luminescence of quantum wells

Deveaud, B.; Kappei, L.; Berney, J.; Morier‐Genoud, F.; Portella‐Oberli, M. T.; Szczytko, Jacek; Piermarocchi, Carlo

doi:10.1016/j.chemphys.2005.06.045

Cited by 23 publications

(25 citation statements)

References 70 publications

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“…46,52 However, it should be emphasized that our observations do not rule out the influence of bi-molecular interactions in the formation kinetics. 50,53,54 Indeed, as explained by Deveaud et al, 55 in the 10 10 cm −2 density range applicable to our current study the Saha and bi-molecular rate-equation models are expected to be largely commensurate, while they deviate at lower densities (see Fig. 7 of Ref.…”

Section: 50mentioning

confidence: 78%

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Transient terahertz spectroscopy of excitons and unbound carriers in quasi-two-dimensional electron-hole gases

et al. 2009

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We report a comprehensive experimental study and detailed model analysis of the terahertz dielectric response and density kinetics of excitons and unbound electron-hole pairs in GaAs quantum wells. A compact expression is given, in absolute units, for the complex-valued terahertz dielectric function of intra-excitonic transitions between the 1s and higher-energy exciton and continuum levels. It closely describes the terahertz spectra of resonantly generated excitons. Exciton ionization and formation are further explored, where the terahertz response exhibits both intra-excitonic and Drude features. Utilizing a two-component dielectric function, we derive the underlying exciton and unbound pair densities. In the ionized state, excellent agreement is found with the Saha thermodynamic equilibrium, which provides experimental verification of the two-component analysis and density scaling. During exciton formation, in turn, the pair kinetics is quantitatively described by a Saha equilibrium that follows the carrier cooling dynamics. The terahertz-derived kinetics is, moreover, consistent with time-resolved luminescence measured for comparison. Our study establishes a basis for tracking pair densities via transient terahertz spectroscopy of photoexcited quasi-two-dimensional electron-hole gases.

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Section: 50mentioning

confidence: 78%

“…7 of Ref. 55). This motivates future work with even more sensitive THz probes to explore formation in the low-intensity limit, and calculations of exciton formation via carrier-carrier interactions in microscopic models.…”

Section: 50mentioning

confidence: 99%

Transient terahertz spectroscopy of excitons and unbound carriers in quasi-two-dimensional electron-hole gases

et al. 2009

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“…Under nonresonant excitation, the PL pulse is characterized by a rise time, τ rise = 10 − 1000 ps, and a decay time, τ decay = 1 − 30 ns, depending on the experimental conditions as well as on the sample design and quality. 3,5,14,[17][18][19][20][21][22][23][24] The theoretical analysis of the data performed in these works and also in Refs. 2,13,15,[25][26][27] al-arXiv:1412.0443v2 [cond-mat.mes-hall] 6 Feb 2015 lowed obtaining characteristic rates of processes occurring mainly in the reservoir of nonradiative excitons.…”

Section: Introductionmentioning

confidence: 99%

Nontrivial relaxation dynamics of excitons in high-quality InGaAs/GaAs quantum wells

et al. 2015

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Photoluminescence (PL) and reflectivity spectra of a high-quality InGaAs/GaAs quantum well structure reveal a series of ultra-narrow peaks attributed to the quantum confined exciton states. The intensity of these peaks decreases as a function of temperature, while the linewidths demonstrate a complex and peculiar behavior. At low pumping the widths of all peaks remain quite narrow (< 0.1 meV) in the whole temperature range studied, 4 -30 K. At the stronger pumping, the linewidth first increases and than drops down with the temperature rise. Pump-probe experiments show two characteristic time scales in the exciton decay, < 10 ps and 15 -45 ns, respectively. We interpret all these data by an interplay between the exciton recombination within the light cone, the exciton relaxation from a nonradiative reservoir to the light cone, and the thermal dissociation of the nonradiative excitons. The broadening of the low energy exciton lines is governed by the radiative recombination and scattering with reservoir excitons while for the higher energy states the linewidths are also dependent on the acoustic phonon relaxation processes.

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“…Finally, ⌫ tr2 is trion formation rate through two-particle in- teraction: an exciton plus a free electron ͑hole͒ for the negative ͑positive͒ trion. An extensive analysis of these times can be found in the papers of Esser et al 2 and Deveaud et al 8 Although the majority of coefficients takes into account the mass action law ͑Saha-Eggert relations͒, we have considered that the process of exciton formation is much faster than the generation of trions and the annihilation of both excitons and trions. 4 Actually, ⌫ tr2 corresponds to the scattering rate of excitons with free electrons, which give rise to the trion formation.…”

Section: ͑5͒mentioning

confidence: 99%

“…Some authors claim that both species can coexist. 8 We consider this possibility in calculations. Short intense laser pulses can also create neutral biexcitons ͑XX͒, which give place to an absorption line some few millielectron volt below the exciton line, close to that of the positive trions.…”

Section: Introductionmentioning

confidence: 98%

Effect of the shape and duration of excitation pulse on the dynamics of excitons and trions in quantum wells

Aceituno

Hernández‐Cabrera

2008

Phys. Rev. B

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We have studied the effect of the shape and duration of a photoexcitation pulse on the temporal evolution of excited electrons when they are both free or bounded in excitons and trions. A quantum well with n-and p-type remotely doped regions is considered to get the necessary excess of free electrons or holes. This configuration allows us to study the evolution of both negative and positively charged excitons simultaneously. Calculations have been done using the matrix density formalism to introduce different pulse types. The temporal behavior of the photoluminescence intensity, which is associated with plasma, exciton, and trion, is obtained by means of the two-dimensional density evolution of the different species.

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Excitonic effects in the luminescence of quantum wells

Cited by 23 publications

References 70 publications

Transient terahertz spectroscopy of excitons and unbound carriers in quasi-two-dimensional electron-hole gases

Transient terahertz spectroscopy of excitons and unbound carriers in quasi-two-dimensional electron-hole gases

Nontrivial relaxation dynamics of excitons in high-quality InGaAs/GaAs quantum wells

Effect of the shape and duration of excitation pulse on the dynamics of excitons and trions in quantum wells

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