Subpicosecond kinetics of band-edge absorption in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>0.25</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>0.75</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>As

Nunnenkamp, J.; Jh, Collet; Klebniczki, J.; Kühl, J.

doi:10.1103/physrevb.43.14047

Cited by 40 publications

(20 citation statements)

References 37 publications

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“…The line shape of the PT spectra indicates that one observes only a bleaching of the excitonic absorption but no noticeable broadening or shift of the excitonic resonances. The latter is explained by the fact that the reduction of the exciton binding energy due to screening is compensated by band-gap renormalization [25][26][27] resulting from a change of the single particle states under photoexcitation.…”

Section: Results and Discussion Of The Carrier Capturementioning

confidence: 99%

Carrier capture in ultrathin InAs/GaAs quantum wells

et al. 2000

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The carrier capture into ultrathin InAs layers embedded in a GaAs matrix has been investigated by timeresolved two-wavelength pump-probe phototransmission at 4.2 K. Using an InAs thickness of 1.2 monolayers, we observe switching of the carrier relaxation from optical to acoustic phonon emission. At the light-hole ͑lh͒ exciton transition we find a constant capture time of 20 ps. In contrast, the capture time decreases abruptly from 50 ps to 22 ps within the heavy-hole ͑hh͒ exciton transition as the energy separation between lh and hh states exceeds the threshold for GaAs LO phonon emission. The combination of both characteristics provides strong evidence for a two-step capture process of the holes. First the holes are captured by the weakly confined lh state and then they cool down to the hh state. We calculated the transient bleaching of the excitonic absorption considering both phase-space filling and exciton screening. The calculations show in agreement with the measurements that the phototransmission transients directly reflect the population of the confined InAs states only at excitation densities below 3ϫ10 8 cm Ϫ2 . At larger excitation densities, the phototransmission rise time becomes significantly smaller than the capture times whereas its decay time appears longer than the carrier lifetime.

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Section: Results and Discussion Of The Carrier Capturementioning

confidence: 99%

Carrier capture in ultrathin InAs/GaAs quantum wells

et al. 2000

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“…Therefore, the development of ultrashort laser pulses has triggered much effort to clarify the initial stages of carrier relaxation and to detect nonthermal carrier distributions and the subsequent transition into the thermal regime. The temporal evolution of carrier-induced optical nonlinearities has been intensively studied in GaAs, A1GaAs, InP and quantum well structures mainly by pump-probe [1][2][3][4][5][6] and time-resolved photoluminescence measurements . Carrier-carrier scattering in bulk GaAs and quantum wells has also been studied by four-wave-mixing measurements of interband polarization dephasing [12][13][14].…”

Section: U-introductionmentioning

confidence: 99%

<title>Internal thermalization of the electron-hole plasma in the subpicosecond regime in GaAs</title>

et al. 1994

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“…[25][26][27] (ii) On a time scale of 100 to 200 fs, the nonthermal energy distribution becomes thermalized, but still hot. [29][30][31] (iii) This distribution then cools close to the initial sample temperature on a time scale of a few ps. 32 (iv) On a much longer time scale, the excited carriers eventually recombine across the gap, producing a fully equilibrated state.…”

Section: A Assignment Of Decay Timesmentioning

confidence: 99%

“…The pump pulse initially creates a CB electron distribution that can be characterized as having a degree of (quantum) coherence, 25,26 both anisotropic and isotropic momentum-space components, 27,28 and a nonthermal energy distribution. 22,23,29,30 Carrier-carrier and carrier-phonon scattering relaxes these components in several, approximately sequential, ways. (i) On a time scale of a few 10s of femtoseconds the coherence disappears and the anisotropic component relaxes, resulting in an isotropic, incoherent distribution in momentum space.…”

Section: A Assignment Of Decay Timesmentioning

confidence: 99%

Carrier capture dynamics of single InGaAs/GaAs quantum-dot layers

Chauhan

Riffe

Everett

et al. 2013

Journal of Applied Physics

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Using 800 nm, 25-fs pulses from a mode locked Ti:Al 2 O 3 laser, we have measured the ultrafast optical reflectivity of MBE-grown, single-layer In 0.4 Ga 0.6 As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and annealing temperature. With increasing excited carrier density, the capture rate decreases; this slowing of the dynamics is attributed to Pauli state blocking within the InGaAs quantum layer.

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Subpicosecond kinetics of band-edge absorption inAl0.25Ga0.75As

Cited by 40 publications

References 37 publications

Carrier capture in ultrathin InAs/GaAs quantum wells

Carrier capture in ultrathin InAs/GaAs quantum wells

<title>Internal thermalization of the electron-hole plasma in the subpicosecond regime in GaAs</title>

Carrier capture dynamics of single InGaAs/GaAs quantum-dot layers

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