Exciton formation and relaxation in GaAs epilayers

Gurioli, Massimo; Borri, Paola; Colocci, M.; Gulia, M.; Rossi, Fausto; Molinari, Elisa; Selbmann, P.E.; Lugli, Paolo

doi:10.1103/physrevb.58.r13403

Cited by 39 publications

(19 citation statements)

References 8 publications

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“…Time-resolved photoluminescence spectroscopy is widely used to investigate the kinetics of free exciton formation, relaxation, and recombination in semiconductors and their nanostructures [1]. In most experiments performed at low lattice temperatures a significantly delayed onset of the free exciton luminescence with respect to the excitation laser pulse is observed [2][3][4][5][6][7][8][9][10][11][12][13]. This slow photoluminescence (PL) rise has attracted intense research interest for nearly three decades.…”

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confidence: 99%

Thermodynamic origin of the slow free exciton photoluminescence rise in GaAs

et al. 2016

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We use time-resolved photoluminescence (TRPL) spectroscopy to unequivocally clarify the microscopic origin of the nanosecond free exciton photoluminescence rise in GaAs at low temperatures. In crucial distinction from previous work, we examine the TRPL of the GaAs free exciton second LO-phonon replica. This enables us to simultaneously monitor the unambiguous time evolution of the total exciton population and the cooling dynamics of the initially hot free exciton ensemble. We demonstrate by a model based on the Saha equation and the experimentally determined cooling behavior that the long-debated slow photoluminescence rise is caused by time-dependent shifts in the thermodynamic quasiequilibrium between free excitons and the uncorrelated electron-hole plasma.

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confidence: 99%

Thermodynamic origin of the slow free exciton photoluminescence rise in GaAs

et al. 2016

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“…9 Thus, the literature provides a wide spectrum of experimental data with rise times increasing 10 or decreasing 7,8,[11][12][13] when raising the excitation density. On the other hand, in bulk III-V samples, these time-resolved studies are scarce [14][15][16][17] and ascertain that the free-exciton PL rise time is strongly influenced by trapping in localization centers.…”

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confidence: 99%

Interplay of exciton and electron-hole plasma recombination on the photoluminescence dynamics in bulk GaAs

et al. 2006

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We present a systematic study of the exciton/electron-hole plasma photoluminescence dynamics in bulk GaAs for various lattice temperatures and excitation densities. The competition between the exciton and electron-hole pair recombination dominates the onset of the luminescence. We show that the metal-to-insulator transition, induced by temperature and/or excitation density, can be directly monitored by the carrier dynamics and the time-resolved spectral characteristics of the light emission. The dependence on carrier density of the photoluminescence rise time is strongly modified around a lattice temperature of 49 K, corresponding to the exciton binding energy (4.2 meV). In a similar way, the rise-time dependence on lattice temperature undergoes a relatively abrupt change at an excitation density of 120-180x10 15 cm -3 , which is about five times greater than the calculated Mott density in GaAs taking into account many body corrections.

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“…Scaling this value to the 2D case one can get g 2D % 10 cm 2 s ± ±1 . Note that g 2D values in the range of 6 to 14 cm 2 s ± ±1 were extracted from the time-resolved study of exciton dynamics at high excitation levels [12,13]. Thus, the values obtained from the PMAE analysis of g and A are reasonable.…”

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confidence: 92%

Combined Optical-Microwave Study of Electron–Exciton Dynamic Processes in Undoped GaAs/AlGaAs Quantum Wells

Ashkinadze

Iomin

Kozhevnikov

et al. 2000

phys. stat. sol. (a)

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Microwave radiation (36 GHz) absorption by photogenerated electrons is combined with photoluminescence (PL) and its excitation (PLE) spectra in order to study electron±exciton dynamics under low photoexcitation intensity in undoped GaAs/AlGaAs quantum wells. The excitation spectra of the photoinduced microwave absorption (PMA) and the PLE spectra are modified with increasing the lattice temperature from 2 up to 80 K. The observed spectral variations are analyzed using a rate equations model that is based on the main generation±recombination and dissociation processes governing the electron and exciton dynamics. We find that the temperature dependence of the PMA excitation spectrum can be well accounted for by assuming both thermal and non-thermal, Auger-like exciton dissociation mechanisms. The model fitting yields an estimate of the rate coefficients for the exciton formation and dissociation processes.

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Exciton formation and relaxation in GaAs epilayers

Cited by 39 publications

References 8 publications

Thermodynamic origin of the slow free exciton photoluminescence rise in GaAs

Thermodynamic origin of the slow free exciton photoluminescence rise in GaAs

Interplay of exciton and electron-hole plasma recombination on the photoluminescence dynamics in bulk GaAs

Combined Optical-Microwave Study of Electron–Exciton Dynamic Processes in Undoped GaAs/AlGaAs Quantum Wells

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