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Bohnert, K.; Kalt, H.; Smirl, Arthur L.; Norwood, D. P.; Boggess, Thomas F.; D’Haenens, I. J.

doi:10.1103/physrevlett.60.37

Cited by 29 publications

(1 citation statement)

References 14 publications

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“…As schematically shown in figure 40, the presence of an indirect gap at energy quasi-resonant to the direct gap causes the simultaneous band filling of different bands with strong alterations of the EHP luminescence spectra. This has been studied in detail in some bulk semiconductors like GaSe (Cingolani, Ferrara and Lugara 1987) where the indirect energy gap is about 25 meV lower in energy than the F point gap, and in the ternary alloy AI~Gal _~As close to the direc~indirect crossover (x-~0.4) (Bohnert, Kalt, Smirl, Norwood, Bogges and D'Haenens 1988 Bohnert, Smirl and Bogges 1988). The basic result of these studies is that, despite the small matrix element of the indirect transitions, radiative recombination from the indirect EHP can occur if the two gaps are not widely separated in the energy space.…”

Section: Many-body Effects In the Spontaneous Luminescence Of Semicon...mentioning

confidence: 99%

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Cingolani

Ploog

1991

Advances in Physics

190

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In this paper we review the radiative recombination processes occurring in semiconductor quantum wells and superlattices under different excitation conditions. We consider processes whose radiative efficiency depends on the photogenerated density of elementary excitations and on the frequency of the exciting field, including luminescence induced by multiphoton absorption, exciton and biexciton radiative decay, luminescence arising from inelastic excitonic scattering, and electron~hole plasma recombination.Semiconductor quantum wells are ideal systems for the investigation of radiative recombinationprocesses at different carrier densities owing to the peculiar wavefunction confinement which ~nhances the optical non-linearities and the bistable behaviour of the crystal. Radiative recombination processes induced by multi-photon absorption processes can be studied by exciting the crystal in the transparency region under an intense photon flux. The application of this nonlinear spectroscopy gives direct access to the excited excitonic states in the quantum wells owing to the symmetry properties and the selection rules for artificially layered semiconductor heterostructures.Different radiative recombination processes can be selectively tuned at exciting photon energies resonant with real states or in the continuum of the conduction band depending on the actual density of photogenerated carriers. We define three density regimes in which different quasi-particles are responsible for the dominant radiative recombination mechanisms of the crystal: (i) The dilute boson gas regime, in which exciton density is lower than 1010 cm-2. Under this condition the decay of free and bound excitons is the main radiative recombination channel in the crystal. (ii) The intermediate density range (n < 1011 cm -2) at which excitonic molecules (biexcitons) and inelastic excitonic scattering processes contribute with additional decay mechanisms to the characteristic luminescence spectra. (iii) The high density range (n-,~ 1012 cm 2) where screening of the Coutomb interaction leads to exciton ionization. The optical transitions hence originate from the radiative decay of freecarriers in a dense electron-hole plasma.The fundamental theoretical and experimental aspects of the radiative recombination processes are discussed with special attention to the GaAs/AlxGa 1 xAs and Gaxlnt -xAs/Alrln 1 -yAs materials systems. The experimental investigations of these effects are performed in the limit of intense exciting fields by tuning the density of photogenerated quasi-particles and the frequency of the exciting photons. Under these conditions the optical response of the quantum well strongly deviates from the well-known linear excitonic behaviour. The optical properties of the crystal are then no longer controlled by the transverse dielectric constant or by the first-order dielectric susceptibility. They are strongly affected by many-body interactions between the different species of photogenerated quasi-particles, resulting in dramatic changes of the...

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Section: Many-body Effects In the Spontaneous Luminescence Of Semicon...mentioning

confidence: 99%

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Cingolani

Ploog

1991

Advances in Physics

190

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Picosecond Optical Nonlinearities and Stimulated Emission in Indirect Al_xGa_1−xAs

Kalt

Smirl

Boggess

1988

Physica Status Solidi (b)

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The nonlinear optical properties of indirect-gap AI,Gal-&s in the presence of a dense electronhole plasma are studied by picosecond luminescence and transient transmission spectroscopy. The fundamental X-band gap is found to be renormalized by exchange and correlation effects within the plasma. Higher-lying band gaps in the same sample are also renormalized but here the electronexchange contribution t o the narrowing is negligible. Strong plasma-induced nonlinearities like persistent bleaching of absorption, enhanced absorption, and large changes of the refractive index are observed a t the direct absorption edge for lattice temperatures of 16 as well as 293 IS. Stimulated emission from the indirect X-band is made possible by alloy-disorder induced band mixing. Die nichtlinearen optischen Eigenschaften von indirektem AI,Gal -As nach Erzeugung einesElektron-Loch-Plasmas werden mit Hilfe von Lumineszenz-und Transmissionsspektroskopie mit Pikosekunden-Zeitauflosung untersucht. Es wird eine Renormierung der fundamentalen X-Bandkmte durch Austausch-und Korrelationseffekte im Plaema beobachtet. Auch hoherliegende Bandkanten im selben Material werden renormiert, jedoch ist hier der Beitrag der Elektronen-Austauschwechselwirkung vernachlassigbar klein. Starke optische Nichtlin_earitiiten werden gefunden, wie ein Ausbleichen der Absorption, erhohte Absorption und groDe Anderungen des Brechungsindex an der direkten Absorptionskante sowohl bei 15 IZ als such bei Raumtemperatur. Eine Bandmischung aufgrund von Legierungsunordnung ermoglicht die stimulierte Emission aus dem indirekten X-Band.

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The Electron-Hole Plasma in Quasi Two-Dimensional and Three-Dimensional Semiconductors

Klingshirn¹,

Weber²,

Chemla

et al. 1989

NATO ASI Series

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Renormalization of Direct and Indirect Band Gaps in Highly ExcitedAlxGa1−xAs

Cited by 29 publications

References 14 publications

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Picosecond Optical Nonlinearities and Stimulated Emission in Indirect Al_xGa_1−xAs

The Electron-Hole Plasma in Quasi Two-Dimensional and Three-Dimensional Semiconductors

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Renormalization of Direct and Indirect Band Gaps in Highly ExcitedAlxGa1−xAs

Cited by 29 publications

References 14 publications

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Frequency and density dependent radiative recombination processes in III–V semiconductor quantum wells and superlattices

Picosecond Optical Nonlinearities and Stimulated Emission in Indirect AlxGa1−xAs

The Electron-Hole Plasma in Quasi Two-Dimensional and Three-Dimensional Semiconductors

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Product

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Picosecond Optical Nonlinearities and Stimulated Emission in Indirect Al_xGa_1−xAs