Observation of Phonon Bottleneck in Quantum Dot Electronic Relaxation

Urayama, Junji; Norris, Theodore B.; Singh, Jasprit; Bhattacharya, P.

doi:10.1103/physrevlett.86.4930

Cited by 346 publications

(189 citation statements)

References 18 publications

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“…This relaxation is different if an electron-hole pair is present or just a sole electron (doped dot). As expected from the phonon bottleneck effect, inter-shell relaxation in (In,Ga)As/GaAs dots has been observed to be slow by Urayama and coworkers 23 (relaxation time of ∼ 750 ps) as well as Heitz and co-workers 27 (7.7 ns). In contrast, time-resolved optical measurements have clearly demonstrated that this inter-shell decay is a fast process whether a hole is present or not.…”

Section: Characteristic Dynamical Processes Of Excited Electrons mentioning

confidence: 70%

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Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B

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We calculate the P -shell-to-S-shell decay lifetime τ (P → S) of electrons in lens-shaped self-assembled (In,Ga)As/GaAs dots due to Auger electron-hole scattering within an atomistic pseudopotential-based approach. We find that this relaxation mechanism leads to fast decay of τ (P → S) ∼ 1 − 7 ps for dots of different sizes. Our calculated Auger-type P -shell-to-S-shell decay lifetimes τ (P → S) compare well with data in (In,Ga)As/GaAs dots, showing that as long as both electrons and holes are present there is no need for an alternative polaron mechanism.

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Section: Characteristic Dynamical Processes Of Excited Electrons mentioning

confidence: 70%

“…Such a hole relaxation has been found to occur within sub-ps times. 16,23 Moreover, Quochi and co-workers showed that the hole relaxation time depends strongly on temperature: 20 ps at 60 K and 0.8 ps at 300 K (Ref. 24).…”

Section: Characteristic Dynamical Processes Of Excited Electrons mentioning

confidence: 99%

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B

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“…The ultrafast response and high detection efficiency of the integrated SSPDs enables us to probe the PL dynamics at low excitation levels. In such a scenario carrier capture and energy relaxation is inefficient due to the discrete electronic arXiv:1407.0593v3 [cond-mat.mes-hall] 15 Aug 2014 structure of the dots and the absence of Coulomb mediated scattering involving carriers occupying energetically higher discrete states 8 . In particular, an excitation power dependent change in inter-sublevel relaxation times is observed for a single, spatially isolated QD.…”

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confidence: 99%

A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors

Reithmaier

Flassig

Hasch

et al. 2014

Applied Physics Letters

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Using integrated superconducting single photon detectors we probe ultra-slow exciton capture and relaxation dynamics in single self-assembled InGaAs quantum dots embedded in a GaAs ridge waveguide. Time-resolved luminescence measurements performed with on-and off-chip detection reveal a continuous decrease in the carrier relaxation time from 1.22 ± 0.07 ns to 0.10 ± 0.07 ns upon increasing the number of non-resonantly injected carriers. By comparing off-chip time-resolved spectroscopy with spectrally integrated on-chip measurements we identify the observed dynamics in the rise time (τ r ) as arising from a relaxation bottleneck at low excitation levels. From the comparison with the temporal dynamics of the single exciton transition with the on-chip emission signal, we conclude that the relaxation bottleneck is circumvented by the presence of charge carriers occupying states in the bulk material and the two-dimensional wetting layer continuum. A characteristic τ r ∝ P −2/3 power law dependence is observed suggesting Auger-type scattering between carriers trapped in the quantum dot and the two-dimensional wetting layer continuum which circumvents the phonon relaxation bottleneck.Semiconductor based photonic information technology is rapidly being pushed to the quantum limit where single photon states can be generated and manipulated in nanoscale optical circuits 1 . Over recent years quantum dots (QDs) embedded in such semiconductor systems have been shown to be excellent sources of quantum light 2-4 and have shown their suitability for use as a gain medium in QD lasers 5-7 . However, for short response times and fast operation of such devices, injected charge carriers must relax rapidly from continuum wetting layer electronic states into the lasing state. For a fully discrete electronic structure, efficient relaxation is expected to be hindered by phonon bottleneck phenomena 8 , caused by the large energetic spacing of QD energy levels that inhibits single-phonon mediated scattering processes 9 . To directly observe such relaxation bottleneck effects, superconducting single photon detectors (SSPDs) are suitable due to their near unity quantum efficiency and picosecond timing resolution 10,11 . Building up on recent progress in this field 12-14 , we developed highly efficient 15,16 NbNSSPDs on GaAs 17 and demonstrated the monolithic integration of InGaAs QDs as single photon emitters together with waveguides and detectors on a single chip 18 . In this letter, we compare photoluminescence (PL) dynamics recorded from a single dot with confocal off-chip detectors with on-chip PL using integrated SSPDs that provide temporal resolution better than 70 ps. By probing the carrier capture and energy relaxation dynamics

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“…Slow phonon thermalisation [6] has been observed in some nano-structured materials and it might perhaps appear in some large band gap bulk materials like InN with large phononic band * Corresponding author. Tel.…”

Section: Introductionmentioning

confidence: 99%

Electron–phonon energy transfer in hot-carrier solar cells

Ĺuque

Martı́

2010

Solar Energy Materials and Solar Cells

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Observation of Phonon Bottleneck in Quantum Dot Electronic Relaxation

Cited by 346 publications

References 18 publications

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B

A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors

Electron–phonon energy transfer in hot-carrier solar cells

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Observation of Phonon Bottleneck in Quantum Dot Electronic Relaxation

Cited by 346 publications

References 18 publications

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: EfficientNarvaez1, Bester2, Zunger3 2006Phys. Rev. B

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: EfficientNarvaez1, Bester2, Zunger3 2006Phys. Rev. B

A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors

Electron–phonon energy transfer in hot-carrier solar cells

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Resources

About

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B

Carrier relaxation mechanisms in self-assembled(In,Ga)As∕GaAsquantum dots: Efficient
Narvaez
¹
,
Bester
²
,
Zunger
³

2006
Phys. Rev. B