Experimental investigation of the oscillator strength of the exciton transition in GaAs single quantum wells

Poltavtsev, S. V.; Stroganov, Boris V.

doi:10.1134/s1063783410090180

Cited by 23 publications

(21 citation statements)

References 14 publications

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“…Typical spectrum displays heavy-hole, light-hole as well as higher energy exciton transitions located around the GaAs bulk exciton resonance (E > 1.514 eV). The presented spectra demonstrate exciton linewidths narrower than those reported in literature [4,7,8,19]. In particular, the heavy-hole exciton line of the sample P554 has FWHM Γ = 130 µeV [ Fig.…”

Section: A Resonant Reflection From Sqwmentioning

confidence: 72%

“…5(b)] with FWHM = 523 µeV characterizing the super-radiant mode linewidth. With this simplified approximation, we may try to perform further analysis of the resonant line structure based on measurements of reflection spectrum as a function of tempera- ture [4]. This method allows one to extract the radiative linewidth of the super-radiant mode and to separate nonradiative linewidth onto temperature-dependent homogeneous broadening Γ 2 (T ) and inhomogeneous broadening Γ * 2 .…”

Section: B Reflection From Mqw Bragg Structurementioning

confidence: 99%

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Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Poltavtsev

Efimov

Dolgikh

et al. 2014

Solid State Communications

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We study radiative linewidth of exciton resonance in shallow InxGa1−xAs/GaAs single quantum wells as a function of indium concentration in the range x = 0.02...0.10 and well thickness in the range LZ = 1...30 nm using the method of Brewster reflection spectroscopy. Record linewidths of heavyhole exciton resonance of about 130...180 µeV are measured in reflection spectra for single quantum wells with LZ = 2 nm and x = 0.02 at temperature 9 K. In these spectra, the non-radiative linewidth including inhomogeneous broadening can be comparable or even less than radiative linewidth. It is shown that radiative linewidth weakly depends on x and LZ in these ranges. In multiple-quantumwell Bragg structure with ten periods radiative linewidth exceeds inhomogeneous broadening by 4 times.

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Section: A Resonant Reflection From Sqwmentioning

confidence: 72%

Section: B Reflection From Mqw Bragg Structurementioning

confidence: 99%

Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Poltavtsev

Efimov

Dolgikh

et al. 2014

Solid State Communications

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“…In the case of resonant pump excitation to the light-hole exciton resonance (LH-exc) a bleaching of the reflection at the heavy-hole exciton resonance (HH-exc) was observed [8,12]. This effect has monotonous dependency on the pump intensity and is related to the scattering of excitons on excessive pump generated carriers accumulated in the QW.…”

Section: Resultsmentioning

confidence: 99%

“…Still it could not give the full picture of the exciton dynamics due to the difficulty of the factorization of the exciton resonance width. We propose the Brewster angle reflection spectroscopy [8,12,13] as a tool enabling independent measurement of the radiative width and nonradiative broadening of the exciton resonance. In this work we present a joint study of exciton resonance bleaching in single QW by means of PL and reflection spectroscopies and suggest possible means to control and eventually suppress this parasitic effect.…”

Section: Introductionmentioning

confidence: 99%

Bleaching compensation in GaAs/AlGaAs quantum wells by above-barrier illumination

Solovev

Kapitonov

Davydov

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. We report an experimental study of the nonlinear response of single GaAs/AlGaAs quantum well. It was shown that bleaching effect manifested as reversible exciton spectral lines broadening can be suppressed by additional above-barrier illumination. IntroductionOne of the most promising alternatives to current silicon-based electronics is the information processing in purely optical way [1][2][3]. Exciton and excitonic complexes in A3B5 nanostructures strongly interact with light due to the relatively large oscillator strength and could serve as a physical model of two-level system that draws special attention in the area of optical computing. However bleaching effect manifested as reversible exciton spectral line broadening limits usefulness of GaAs/AlGaAs structures in informational photonics.Earlier it was shown that at relatively weak and intermediate intensities exciton bleaching is observed while spectrally integrated peak intensity in the absorption spectrum remains the same [4]. The main mechanism of bleaching is said to be broadening of the exciton line induced by scattering of excitons on carriers and exciton-carriers complexes. Сarriers captured in QW reveal long-lived kinetics in microsecond scale [5]. Moreover PL signal from electron hole pair could be clearly detected up to tens of second after excitation due to non-exponential decay of carrier concentration [6,7]. Bleaching effect could be reduced by lowering of Al percentage in Al Ga 1− As QW barriers down to few percent [8].Carriers could be observed even in nominally undoped quantum wells (QWs) grown by Molecular Beam Epitaxy (MBE) due to the unintentional doping. Presence of carriers in QW leads to the formation of a peak in the photoluminescence (PL) spectrum at energies below exciton recombination line [9] . This peak corresponds to the exction-carrier bound state -trion. Additional optical pump could lead either to the buildup or to the reduction of charge carriers concentration in QW depending on the pump spectral position relative to the band gap [10]. Alterations in carriers concentration or even in their sign [11] may be revealed by analysis of opposing changes in trion and exciton peak amplitudes in PL.PL spectroscopy is generally used for detection of such charged exciton complexes [5,[9][10][11]. Still it could not give the full picture of the exciton dynamics due to the difficulty of the factorization of the exciton resonance width. We propose the Brewster angle reflection

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“…As the main method of studying excitonic properties of the irradiated and nonirradiated epitaxial structures, we used reflection spectroscopy in the Brewster configuration based on the theory developed in . Theoretical consideration of the reflection signal leads to the following expression for spectral behavior of the exciton mirror reflectivity K R ( ω,D ):

K_{R} true(ω, D true) = \frac{Γ_{R}^{2}}{{(ω - ω_{0})}^{2} + {(Γ_{R} + Γ_{2} + Γ_{2}^{*} + normalΔ Γ_{2}^{*} false(D false))}^{2}},

where 2 ℏΓ R is the radiative width of the exciton resonance, 2 ℏΓ 2 and 2 ℏΓ 2 * are its homogeneous and inhomogeneous width, and 2 ℏ Δ Γ 2 * ( D ) is the additional inhomogeneous broadening arising due to irradiation of the sample by ions with the dose D , and ω 0 is the exciton resonance frequency.…”

Section: Methodsmentioning

confidence: 99%

Effect of irradiation by He⁺ and Ga⁺ ions on the 2D‐exciton susceptibility of InGaAs/GaAs quantum‐well structures

Kapitonov

Shapochkin

Petrov

et al. 2015

Physica Status Solidi (b)

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The effect of irradiation by 30‐keV Ga+ and 35‐keV He+ ions (in relatively small doses) on the excitonic reflectivity spectra of single InGaAs/GaAs quantum‐well structures is studied. It is found that the irradiation results in decreasing intensity and broadening of the excitonic resonances in the reflectivity spectra for all the doses. It is shown that these changes are not related to a decrease of the exciton transition oscillator strength and, therefore, to the irradiation‐induced destruction of the excitonic states, but can be rather ascribed to a common cause, namely, to inhomogeneous broadening of the excitonic resonances proportional to the exposure dose. A tentative model of the irradiation‐induced broadening is considered, with the mechanism of the process being a consequence of scattering of the 2D excitons by structural defects associated with Ga(In) and As vacancies arising upon collisions of the high‐energy ions with regular atoms of the crystal structure. The model is used to compare experimental dependence of efficiency of the Ga+‐ion‐induced broadening on distance of the quantum well from the irradiated surface with a similar dependence calculated using the Monte‐Carlo technique. A discrepancy between the results of simulation and experimental data is discussed.

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Experimental investigation of the oscillator strength of the exciton transition in GaAs single quantum wells

Cited by 23 publications

References 14 publications

Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Bleaching compensation in GaAs/AlGaAs quantum wells by above-barrier illumination

Effect of irradiation by He⁺ and Ga⁺ ions on the 2D‐exciton susceptibility of InGaAs/GaAs quantum‐well structures

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Experimental investigation of the oscillator strength of the exciton transition in GaAs single quantum wells

Cited by 23 publications

References 14 publications

Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

Bleaching compensation in GaAs/AlGaAs quantum wells by above-barrier illumination

Effect of irradiation by He+ and Ga+ ions on the 2D‐exciton susceptibility of InGaAs/GaAs quantum‐well structures

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Effect of irradiation by He⁺ and Ga⁺ ions on the 2D‐exciton susceptibility of InGaAs/GaAs quantum‐well structures