Raman study of self-assembled GaAs and AlAs islands embedded in InAs

Ténné, D. A.; Haisler, V. A.; Toropov, A. I.; Bakarov, A. K.; Gutakovsky, A.K.; Zahn, Dietrich R. T.; Shebanin, A. P.

doi:10.1103/physrevb.61.13785

Cited by 38 publications

(36 citation statements)

References 27 publications

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“…Even though, there are rather few experimental studies of RRS in SAQD's so far. Information on phonon modes in the most intensively investigated SAQD system, InAs/GaAs, has been obtained by resonant photoluminescence [5] rather than by Raman scattering, although there are some published studies of SAQD's grown in other heteroepitaxial systems (see [6] and references therein). From the theoretical viewpoint, RRS in SAQD's was considered in Ref.…”

Section: Introductionmentioning

confidence: 99%

Is polaron effect important for resonant Raman scattering in self‐assembled quantum dots?

Vasilevskiy

Miranda²

2005

phys. stat. sol. (c)

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While the diagonal (or intra-level) interaction of a confined exciton with optical phonons in selfassembled quantum dots (SAQD's) is rather weak, the non-diagonal one can lead to a considerable change of the exciton spectrum and the formation of a polaron. An impact of this effect on resonant inelastic light scattering is studied theoretically. The polaron spectrum is obtained by numerical diagonalisation of the exciton -phonon interaction Hamiltonian in a truncated Hilbert space of the non-interacting excitons and phonons. Based on this spectrum, the probability of the multi-phonon Raman scattering is calculated, which is compared to that obtained within the standard perturbation theory approach (where phonon emission and absorption are irreversible). It is shown that there are two major effects of the polaron formation: (i) the intensity of the two-phonon (2 LO) peak, relative to that of the fundamental 1 LO one is strongly increased and (ii) the resonant behaviour of the 1 LO peak differs considerably from the perturbation theory predictions. With the correct theoretical interpretation, resonant Raman scattering in SAQD's opens the possibility of accessing the (renormalised) exciton spectrum and exciton -phonon coupling constants.

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Section: Introductionmentioning

confidence: 99%

Is polaron effect important for resonant Raman scattering in self‐assembled quantum dots?

Vasilevskiy

Miranda²

2005

phys. stat. sol. (c)

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“…Raman spectra of InAs/Al(Ga)As QDs including optical, interface, and acoustical phonon scattering has been widely investigated [2][3][4][5]. As it was shown [5], Raman spectra of these QD structures reveal the resonances by optical phonons which are shifted towards higher energies with respect to their bulk values that manifests compressive strain of the QDs. Confinement of optical phonons in QDs leads to the lowering their phonon energies [2].…”

Section: Introductionmentioning

confidence: 99%

Raman scattering by porous structures with InAs quantum dots

Milekhin¹,

Ursaki²,

Sirbu³

et al. 2009

Phys. Status Solidi (c)

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In this paper we search for the possibilities of introducing porosity in InAs/AlAs/GaAs multilayer quantum dot structures as an additional tool for the modification of their phonon spectrum. Raman spectroscopy is used as a primary method of investigation of quantum dot phonon spectrum. Introduction of porosity in quantum dot structures leads to alteration of optical phonon frequencies in quantum dots due to relaxation of built‐in mechanical strain in quantum dots and appearance of Froehlich modes. Magnification of the Raman replicas by optical phonons in quantum dots is explained by multiple light reflection in the porous structure. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…However, the vibrational spectrum which contains information on the structural properties of QDs (such as size dispersion, shape [2,3] and mechanical strain [4,5]) even in InAs/Ga(Al)As QDs is much less investigated. The knowledge and the possibility to control the phonon spectrum are especially important in potential optoelectronic devices based on QDs, since the phonons influence the relaxation of electronic excitations [1] and the mobility of charge carriers.…”

mentioning

confidence: 99%

“…Several publications [2][3][4][5][7][8][9][10] devoted to experimental (mostly by Raman scattering) and theoretical investigation of optical and interface phonons in InAs/Al(Ga)As QDs have occured recently. As it was shown in [3] optical phonons localized in the QDs are shifted towards higher (lower) energies with respect to their bulk values.…”

mentioning

confidence: 99%

Phonons in InAs quantum dot structures

Milekhin

Toropov

Zahn

2009

Phys. Status Solidi (c)

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We present a Raman study of the phonon spectra of periodical structures with (In,Ga)As QDs in (Al,Ga)As matrix as well as AlAs QDs embedded in InAs grown by molecular beam epitaxy. Raman scattering by optical, interface and acoustic phonons was observed in the QD structures. TO and LO phonons in the QDs are strongly affected by both strain and confinement. The Raman study reveals a two‐mode behavior of optical phonons in the whole composition range for both InGaAs QDs and the AlGaAs matrix. Raman scattering by InAs‐ and GaAs‐like LO phonons in InGaAs QDs shows a size‐selective resonant behaviour. Interface phonons were investigated in InGaAs QDs and the AlGaAs matrix. Their frequency positions were analyzed as a function of the alloy content within the dielectric continuum model. The positions of IF phonons in the QD structures observed in the experiment agree well with calculated ones assuming that the QDs have the shape of oblate ellipsoids. Multiple phonon Raman scattering involving both pure overtones of the first‐order InAs, GaAs and AlAs optical and interface phonons and combination of phonons from the materials is observed in the vicinity with E0 resonance in QDs. Possible mechanisms of these processes are discussed. Low frequency resonant Raman scattering by acoustic phonons was observed in the QD structures. The periodic oscillations seen in the Raman spectra are well described by the elastic continuum model. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Raman study of self-assembled GaAs and AlAs islands embedded in InAs

Cited by 38 publications

References 27 publications

Is polaron effect important for resonant Raman scattering in self‐assembled quantum dots?

Is polaron effect important for resonant Raman scattering in self‐assembled quantum dots?

Raman scattering by porous structures with InAs quantum dots

Phonons in InAs quantum dot structures

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