Chapter 1 Ultrafast electron—Phonon interactions in semiconductors: Quantum kinetic memory effects

Leitenstorfer, Alfred; Laubereau, A.

doi:10.1016/s0080-8784(01)80167-8

Cited by 4 publications

(8 citation statements)

References 52 publications

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“…From the Fourier and wavelet transforms of oscillations measured at 0.064 mJ cm −2 (see figures 7(c) and (e)), one clearly sees a major feature located at ∼5 THz that safely can be identified as the LO phonon frequency of CdTe (see figure 1). In addition to this one observes the LOPC mode formation (L + and L − mode) a few hundred femtoseconds following the laser excitation and, as the carrier density decays, this merges into the 5 THz band 13 . At early times (<500 fs) the time resolution of the experiment (primarily determined by the laser pulse duration of ∼60 fs) allowed us to observe only the low-frequency tail of the damped L + mode.…”

Section: Low Fluence Regime: Longitudinal Phonon-plasmon Coupled Modesmentioning

confidence: 79%

“…In this work we have employed time-resolved reflectivity to investigate the relaxation of hot carriers in the presence of LOPC modes in laser-excited CdTe. CdTe is a polar semiconductor with an intermediate electron-phonon coupling strength that is quantified by the polaron coupling constant 0.4 α , defined in terms of the static and high-frequency di electric constants [13]. Although CdTe is an important material with a wide range of applications such as solar cells, infrared, x-ray and γ-ray detectors [14][15][16], experimental work on its ultrafast dynamics is scarce [13,[17][18][19], especially if one compares it with the very well studied, weakly-coupled ( 0.06 α ) polar semiconductor GaAs.…”

Section: Introductionmentioning

confidence: 99%

“…CdTe is a polar semiconductor with an intermediate electron-phonon coupling strength that is quantified by the polaron coupling constant 0.4 α , defined in terms of the static and high-frequency di electric constants [13]. Although CdTe is an important material with a wide range of applications such as solar cells, infrared, x-ray and γ-ray detectors [14][15][16], experimental work on its ultrafast dynamics is scarce [13,[17][18][19], especially if one compares it with the very well studied, weakly-coupled ( 0.06 α ) polar semiconductor GaAs. In [17], Ishioka et al reported the time-resolved reflectivity on bulk CdTe in a photoexcitation fluence regime of 4.4 to 88 μ J cm −2 .…”

Section: Introductionmentioning

confidence: 99%

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Hot carrier relaxation in CdTe via phonon–plasmon modes

Zhong

Ostach

Scholz

et al. 2017

J. Phys.: Condens. Matter

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Carrier and lattice dynamics of laser excited CdTe was studied by time-resolved reflectivity for excitation fluences spanning about three orders of magnitude, from 0.064 to 6.14 mJ cm. At fluences below 1 mJ cm the transient reflectivity is dominated by the dynamics of hybrid phonon-plasmon modes. At fluences above 1 mJ cm the time-dependent reflectivity curves show a complex interplay between band-gap renormalization, band filling, carrier dynamics and recombination. A framework that accounts for such complex dynamics is presented and used to model the time-dependent reflectivity data. This model suggests that the excess energy of the laser-excited hot carriers is reduced much more efficiently by emitting hybrid phonon-plasmon modes rather than bare longitudinal optical phonons.

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Section: Low Fluence Regime: Longitudinal Phonon-plasmon Coupled Modesmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hot carrier relaxation in CdTe via phonon–plasmon modes

Zhong

Ostach

Scholz

et al. 2017

J. Phys.: Condens. Matter

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“…To a large degree, many fundamental properties of the epitaxially grown II-VI materials depend upon their lattice dynamics and electron-phonon interaction. [69][70][71][72][73] Scattering of thermal neutrons by solids 56 (e.g., ZnS, ZnSe, ZnTe, and CdTe) is by far the most useful tool for studying lattice vibrations, since their interaction extends over almost the entire range of energies and wave vectors in the Brillouin zone. Unfortunately, the neutron scattering method cannot be applied to thin films or nanostructured materials (SLs and/or quantum wells, etc.)…”

Section: Introductionmentioning

confidence: 99%

Infrared reflectance and transmission spectra in II-VI alloys and superlattices

et al. 2011

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Room temperature measurements of the far-infrared (FIR) reflectance spectra are reported for the polar optical phonons in a series of bulk Cd x Zn 1−x Te (0 x 1) and CdSe x Te 1−x (0 < x 0.35) crystals grown by Bridgman technique. The composition-dependent spectra exhibited many fundamental aspects of lattice vibrations, while the results of long-wavelength optical modes for the end member binary compounds displayed phonon values in good agreement with the existing inelastic neutron scattering and/or Raman spectroscopy data. Using a standard methodology of multilayer optics with effective-medium dielectric tensors, we simulated the FIR transmission and reflectivity spectra at oblique incidence (Berreman's effect) in many II-VI free-standing thin films, epilayers and superlattices. Berreman's approach provided us with a strong basis for analyzing the infrared experimental data and offered an effective means of estimating the zone-center transverse and longitudinal optical (ω TO , ω LO) phonon frequencies in polar-semiconductor thin films and heterostructure materials of increasing technological importance.

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“…They can evolve from their initial linear polarization to elliptical and circular as they propagate through the device. This introduces additional considerations-for example, if counter-circularly polarized pump and probe signals are used, angular momentum considerations lead to a decoupling of the spin populations and the signals do not couple to the same conduction band to light/heavy hole valence band transitions [21], [22]. Therefore, different behavior could be expected for cocircular and countercircular pump-probe configurations.…”

Section: A Gain Dynamicsmentioning

confidence: 99%

Experimental Investigation of Polarization Effects in Semiconductor Optical Amplifiers and Implications for All-Optical Switching

Philippe

Bradley

Kennedy

et al. 2008

J. Lightwave Technol.

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Abstract-A free-space contra-propagation configuration is implemented and pump-probe studies are undertaken in order to study polarization-dependent gain dynamics in bulk semiconductor optical amplifiers (SOAs) and their application to gain and polarization switching. The polarization dependence of the gain compression shows that the co-polarized case, in which the pump and probe are TE-polarized, is the optimum for gain switching. When injecting light polarized at 45 , an additional contribution due to the presence of rotating fields is observed, and the cross-polarized case is found to be the most promising for polarization switching. The potential for all-optical switching based on nonlinear polarization rotation (NLPR) induced in the SOA is then assessed through characterization of the dynamics of the state of polarization. It is demonstrated that by careful selection of the orientation of a linear polarizer in front of the detector, it is possible to reduce the recovery time from 100 to 5 ps. The improvement comes about from the selection of the intraband fast gain recovery dynamics. Polarization switching offers potentially faster switching times compared to gain switching as well as an extinction ratio improvement of 10 dB.

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Chapter 1 Ultrafast electron—Phonon interactions in semiconductors: Quantum kinetic memory effects

Cited by 4 publications

References 52 publications

Hot carrier relaxation in CdTe via phonon–plasmon modes

Hot carrier relaxation in CdTe via phonon–plasmon modes

Infrared reflectance and transmission spectra in II-VI alloys and superlattices

Experimental Investigation of Polarization Effects in Semiconductor Optical Amplifiers and Implications for All-Optical Switching

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