Time-resolved photon echoes from donor-bound excitons in ZnO epitaxial layers

Poltavtsev, S. V.; Kosarev, A.; Акимов, И. А.; Yakovlev, D. R.; Sadofev, Sergey; Puls, J.; Hoffmann, Sandro Phil; Albert, Maximilian; Meier, Cedrik; Meier, Torsten; Bayer, М.

doi:10.1103/physrevb.96.035203

Cited by 12 publications

(20 citation statements)

References 30 publications

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“…The lowtemperature part of the temperature dependence of the decoherence rate can be approximated with a linear dependence Γ 2 = Γ 0 2 + γT . The slope γ = 0.8 µeV/K responsible for the exciton dephasing due to interaction with acoustic phonons is somewhat smaller than that observed recently in ZnO bulk and QWs (∼ 2 µeV/K) [19,21]. It can be concluded, however, that acoustic phonons strongly and unavoidably damp exciton coherence in (In,Ga)N/GaN QWs.…”

Section: Fwm Experimental Resultscontrasting

confidence: 55%

Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

et al. 2018

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We study the coherent dynamics of localized excitons in 100-periods of 2.5 nm thick (In,Ga)N/GaN quantum wells with 7.5% indium concentration, measured with spectroscopic resolution through two-pulse and three-pulse photon echoes at the temperature of 1.5 K. A long-lived coherent exciton dynamics is observed in the (In,Ga)N quantum wells: When the laser photon energy is tuned across the 43 meV-wide inhomogeneously broadened resonance line, the coherence time T2 varies between 45 and 255 ps, increasing with stronger exciton localization. The corresponding narrow homogeneous linewidths ranging from 5.2 to 29 µeV as well as the relatively weak exciton-phonon interaction (0.8 µeV/K) confirm a strong, quantum dot-like exciton localization in a static disordered potential inside the (In,Ga)N quantum well layers.

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Section: Fwm Experimental Resultscontrasting

confidence: 55%

Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

et al. 2018

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“…Here, it is assumed that the inhomogeneous broadening Γ = 1/σ is significantly larger than the homogeneous broadening γ = 1/T 2 . This condition is fulfilled for the optical transitions to the localized X − and D 0 X complexes [25,[30][31][32]. The rephasing spectra for the co-and cross-polarized configurations are plotted in Figs.…”

Section: Two-dimensional Fourier Spectra In Nanostructures With Rmentioning

confidence: 99%

High-Resolution Two-Dimensional Optical Spectroscopy of Electron Spins

et al. 2017

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Multidimensional coherent optical spectroscopy is one of the most powerful tools for investigating complex quantum mechanical systems. While it was conceived decades ago in magnetic resonance spectroscopy using micro-and radio-waves, it has recently been extended into the visible and UV spectral range. However, resolving MHz energy splittings with ultrashort laser pulses has still remained a challenge. Here, we analyze two-dimensional Fourier spectra for resonant optical excitation of resident electrons to localized trions or donor-bound excitons in semiconductor nanostructures subject to a transverse magnetic field. Particular attention is devoted to Raman coherence spectra which allow one to accurately evaluate tiny splittings of the electron ground state and to determine the relaxation times in the electron spin ensemble. A stimulated step-like Raman process induced by a sequence of two laser pulses creates a coherent superposition of the ground state doublet which can be retrieved only optically due to selective excitation of the same sub-ensemble with a third pulse. This provides the unique opportunity to distinguish between different complexes that are closely spaced in energy in an ensemble. The related experimental demonstration is based on photon echo measurements in an n-type CdTe/(Cd,Mg)Te quantum well structure detected by a heterodyne technique. The difference in the sub-µeV range between the Zeeman splittings of donor-bound electrons and electrons localized at potential fluctuations can be resolved even though the homogeneous linewidth of the optical transitions is larger by two orders of magnitude.

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“…CdTe/(Cd,Mg)Te QWs [22][23][24], ZnSe/(Zn,Mg)(S,Se) QWs, (In,Ga)As/GaAs QDs as well as ZnO epitaxial layers [26]. The resonances in QWs and bulk materials possess large oscillator strength, which does not cause problems with the detection of FWM signal.…”

Section: The Studied Objects Are Various a 2 B 6 And A 3 B 5 Epitaxiamentioning

confidence: 99%

“…In the paper the main effects are considered for a model system -CdTe/(Cd,Mg)Te quantum wells (QWs), where inhomogeneous broadening of the optical transitions is small and it is possible to excite selectively the various exciton complexes with the different degree of localization [24,25]. We also consider the photon echo signals in the hexagonal epitaxial ZnO layers [26], ZnSe/(Zn,Mg)(S,Se) QWs and self-organized (In,Ga)As/GaAs quantum dots (QDs) placed inside the planar microcavities in order to enhance the exciton-light coupling. The experimental results are obtained by means of the four-wave-mixing with heterodyne detection described in section 2.…”

Section: Introductionmentioning

confidence: 99%

Photon Echo from Localized Excitons in Semiconductor Nanostructures

et al. 2018

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An overview on photon echo spectroscopy under resonant excitation of the exciton complexes in semiconductor nanostructures is presented. The use of four-wavemixing technique with the pulsed excitation and heterodyne detection allowed us to measure the coherent response of the system with the picosecond time resolution. It is shown that, for resonant selective pulsed excitation of the localized exciton complexes, the coherent signal is represented by the photon echoes due to the inhomogeneous broadening of the optical transitions. In case of resonant excitation of the trions or donor-bound excitons, the Zeeman splitting of the resident electron ground state levels under the applied transverse magnetic field results in quantum beats of photon echo amplitude at the Larmor precession frequency. Application of magnetic field makes it possible to transfer coherently the optical excitation into the spin ensemble of the resident electrons and to observe a long-lived photon echo signal. The described technique can be used as a high-resolution spectroscopy of the energy splittings in the ground state of the system. Next, we consider the Rabi oscillations and their damping under excitation with intensive optical pulses for the excitons complexes with a different degree of localization. It is shown that damping of the echo signal with increase of the excitation pulse intensity is strongly manifested for excitons, while on trions and donor-bound excitons this effect is substantially weaker.

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Time-resolved photon echoes from donor-bound excitons in ZnO epitaxial layers

Cited by 12 publications

References 30 publications

Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

High-Resolution Two-Dimensional Optical Spectroscopy of Electron Spins

Photon Echo from Localized Excitons in Semiconductor Nanostructures

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