Exciton acoustic-phonon coupling in single GaN/AlN quantum dots

Остапенко, І. А.; Hönig, Gerald; Rodt, Sven; Schliwa, A.; Hoffmann, A.; Bimberg, D.; Dachner, Matthias‐René; Richter, Marten; Knorr, Andreas; Kako, Satoshi; Arakawa, Yasuhiko

doi:10.1103/physrevb.85.081303

Cited by 47 publications

(46 citation statements)

References 35 publications

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“…The latter process must be efficient to explain the occurrence of intense X emission besides the hybrid-XX emission. Excitonic spin-flip times of QDs in the order of ps have already been reported 48 and acoustic phonon coupling to excitons in GaN/AlN QDs is exceptionally strong 49,50 .…”

Section: Resultsmentioning

confidence: 99%

Manifestation of unconventional biexciton states in quantum dots

et al. 2014

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Although semiconductor excitons consist of a fermionic subsystem (electron and hole), they carry an integer net spin similar to Cooper-electron-pairs. While the latter cause superconductivity by forming a Bose-Einstein-condensate, excitonic condensation is impeded by, for example, a fast radiative decay of the electron-hole pairs. Here, we investigate the behaviour of two electron-hole pairs in a quantum dot with wurtzite crystal structure evoking a charge carrier separation on the basis of large spontaneous and piezoelectric polarizations, thus reducing carrier overlap and consequently decay probabilities. As a direct consequence, we find a hybrid-biexciton complex with a water molecule-like charge distribution enabling anomalous spin configurations. In contrast to the conventional-biexciton complex with a net spin of s ¼ 0, the hybrid-biexciton exhibits s ¼ ± 3, leading to completely different photoluminescence signatures in addition to drastically enhanced charge carrier-binding energies. Consequently, the biexcitonic cascade via the dark exciton can be enhanced on the rise of temperature as approved by photon cross-correlation measurements.

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Section: Resultsmentioning

confidence: 99%

Manifestation of unconventional biexciton states in quantum dots

et al. 2014

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“…However, the S line also intensifies with rising indium content, which we tentatively attribute to disorderinduced phonon-confinement, boosting the exciton-phonon interaction as commonly observed for nanostructures. [44][45][46] VI. SUMMARY In summary, we have presented a detailed analysis of the excited states related to the neutral silicon donor bound exciton (Si 0 X n¼1 A ) in a high quality GaN epilayer.…”

Section: A Isotope Effect In Ganmentioning

confidence: 99%

Excited states of neutral donor bound excitons in GaN

Callsen

Kure

Wagner

et al. 2018

Journal of Applied Physics

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We investigate the excited states of a neutral donor bound exciton (D0X) in bulk GaN by means of high-resolution, polychromatic photoluminescence excitation (PLE) spectroscopy. The optically most prominent donor in our sample is silicon accompanied by only a minor contribution of oxygen—the key for an unambiguous assignment of excited states. Consequently, we can observe a multitude of Si0X-related excitation channels with linewidths down to 200 μeV. Two groups of excitation channels are identified, belonging either to rotational-vibrational or electronic excited states of the hole in the Si0X complex. Such identification is achieved by modeling the excited states based on the equations of motion for a Kratzer potential, taking into account the particularly large anisotropy of effective hole masses in GaN. Furthermore, several ground- and excited states of the exciton-polaritons and the dominant bound exciton are observed in the photoluminescence (PL) and PLE spectra, facilitating an estimate of the associated complex binding energies. Our data clearly show that great care must be taken if only PL spectra of D0X centers in GaN are analyzed. Every PL feature we observe at higher emission energies with regard to the Si0X ground state corresponds to an excited state. Hence, any unambiguous peak identification renders PLE spectra highly valuable, as important spectral features are obscured in common PL spectra. Here, GaN represents a particular case among the wide-bandgap, wurtzite semiconductors, as comparably low localization energies for common D0X centers are usually paired with large emission linewidths and the prominent optical signature of exciton-polaritons, making the sole analysis of PL spectra a challenging task.

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“…Like all the other results discussed in this review, the calculations shown in Fig. 15 correspond to the weak coupling limit realized for InGaAs-type QDs, while for other materials such as, e.g., GaN, the carrierphonon coupling can be substantially stronger [55,67]. Thus, in contrast to the other preparation protocols discussed in this review, which work best in the absence of the carrier-phonon coupling, the phonon-assisted preparation based on off-resonant driving performs the better the stronger the carrier-phonon coupling is [211].…”

Section: Phonon Assisted Exciton and Biexciton Preparationmentioning

confidence: 94%

“…The interaction with optical phonons gives rise to satellites in the spectrum separated by multiples of the optical phonon frequency, which again are superimposed on a background due to the acoustic phonons. This type of spectra has been seen in many experimental and theoretical studies [50,78,51,62,67].…”

Section: Rabi Rotationsmentioning

confidence: 95%

“…Additional structures in the spectral density appear as soon as other characteristic length scales are present in the system. Phonon couplings for various types of QD structures with more than one length scale have been discussed in the literature, such as QDs with different confinement lengths of electrons and holes [66] or with different aspect ratios [67], strong variations of the acoustic properties at the boundary of the QD [68], a QD placed close to a surface [69], in free-standing slab [69,70] or in a quantum wire [71], or a pair of QDs at a given distance [72,73].…”

Section: Quantum Dot Modelmentioning

confidence: 99%

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The role of phonons for exciton and biexciton generation in an optically driven quantum dot

Reiter

Kuhn

Glässl

et al. 2014

J. Phys.: Condens. Matter

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Abstract. For many applications of semiconductor quantum dots in quantum technology a well controlled state preparation of the quantum dot states is mandatory. Since quantum dots are embedded in the semiconductor matrix, the interaction with phonons plays often a major role in the preparation process. In this review, we discuss the influence of phonons on three basically different optical excitation schemes which can be used for the preparation of exciton, biexciton, and superposition states: a resonant excitation leading to Rabi rotations in the excitonic system, an excitation with chirped pulses exploiting the effect of adiabatic rapid passage, and an off-resonant excitation giving rise to a phononassisted state preparation. We give an overview over experimental and theoretical results showing the role of the phonons and compare the performance of the schemes for state preparation.

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Exciton acoustic-phonon coupling in single GaN/AlN quantum dots

Cited by 47 publications

References 35 publications

Manifestation of unconventional biexciton states in quantum dots

Manifestation of unconventional biexciton states in quantum dots

Excited states of neutral donor bound excitons in GaN

The role of phonons for exciton and biexciton generation in an optically driven quantum dot

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