Raman study of interface modes subjected to strain in InAs/GaAs self-assembled quantum dots

Pusep, Yu. A.; Zanelatto, G.; Silva, S. W. da; Galzerani, J. C.; González‐Borrero, Pedro Pablo; Toropov, A. I.; Basmaji, P.

doi:10.1103/physrevb.58.r1770

Cited by 56 publications

(23 citation statements)

References 18 publications

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“…In Ref. 13 we have already found the TO and LO phonons in InAs/GaAs SAQDs at 250 cm -1 and 260 cm -1 , respectively. Therefore, we here assign the line observed at 250 cm -1 to the TO phonon of InAs, while no contribution was found at the frequencies where the LO phonons of InAs were expected.…”

Section: Resultsmentioning

confidence: 75%

Effects of annealing on electrical and optical properties of a multilayer InAs/GaAs quantum dots system

et al. 2004

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A systematic investigation of the properties of the InAs/GaAs self-assembled quantum dots (SAQDs) system subjected to a post-growth annealing using capacitance-voltage, Raman scattering and photoluminescence measurements is presented. The application of both electrical and optical methods allowed us to obtain reliable information on the microscopic structural evolution of this system. The single layer and the multilayer quantum dots were found to respond differently to the annealing process, due to the differences in strain that occur in both systems. The diffusion activated by strain provoked the appearance of an InGaAs alloy layer in substitution to the quantum dots layers; this change occurred at the annealing temperature T = 600 °C in the multilayer system. A single dot layer, however, was observed even after the annealing at T = 700 °C. Moreover, the low temperature annealing was found to improve the homogeneity of the multilayer system and to decrease the electrical interlayer coupling.

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Section: Resultsmentioning

confidence: 75%

Effects of annealing on electrical and optical properties of a multilayer InAs/GaAs quantum dots system

et al. 2004

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“…This large dipole moment allows us to easily tune the interdot exciton states into resonance with states consisting of the |X 0 S exciton and one optical phonon, labelled |X 0 ,OS, which for InAs/GaAs-QDs are between 28 and 38 meV above the involved exciton state. These exciton-phonon states, socalled polarons, are continuous because of the k-space dispersion of the optical phonons, strain, intermixing of InAs and GaAs, and interface effects 40,41 . Optical transitions between all those states and the crystal ground state, |cgsS, map the level structure of a QDM one to one into the optical spectrum.…”

Section: Resultsmentioning

confidence: 99%

Optophononics with coupled quantum dots

et al. 2014

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Modern technology is founded on the intimate understanding of how to utilize and control electrons. Next to electrons, nature uses phonons, quantized vibrations of an elastic structure, to carry energy, momentum and even information through solids. Phonons permeate the crystalline components of modern technology, yet in terms of technological utilization phonons are far from being on par with electrons. Here we demonstrate how phonons can be employed to render a single quantum dot pair optically transparent. This phonon-induced transparency is realized via the formation of a molecular polaron, the result of a Fano-type quantum interference, which proves that we have accomplished making typically incoherent and dissipative phonons behave in a coherent and non-dissipative manner. We find the transparency to be widely tunable by electronic and optical means. Thereby we show amplification of weakest coupling channels. We further outline the molecular polaron's potential as a control element in phononic circuitry architecture.

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“…7) with energies of 30.3, 33.2, and 35.8 meV. Resonant Raman experiments exciting the E1 bandgap [67] indicate the 35.8 meV mode to be an interface mode associated with the apex of the pyramids. The 33.2 meV mode is attributed to the strained InAs LO mode in good agreement with predictions based on the average strain in coherent InAs/GaAs pyramids [43], supporting pyramid-like InAs/GaAs QD's in the investigated samples.…”

Section: Introductionmentioning

confidence: 95%

“…The phonon modes of self-organized InAs/GaAs QD's have been observed in PLE experiments [23,65,66] as well as in resonant Raman scattering experiments, exciting either the E1 bandgap of bulk InAs [67] or the QD ground state [63]. Exciting in the low-energy slope of the QD PL (Fig.…”

Section: Introductionmentioning

confidence: 96%

Exciton–LO‐phonon coupling in self‐organized InAs/GaAs quantum dots

Heitz

Schliwa

Bimberg

2003

Physica Status Solidi (b)

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Dedicated to Professor Jozef T. Devreese on the occasion of his 65th birthday PACS 73.21.La, 78.20.Hp, 78.35.+c, 78.67.HcThe exciton-LO-phonon interaction in self-organized quantum dots is investigated emphasizing the impact of realistic structural properties. The possibility to engineer the local charge density via the shape and composition profile of such strained quantum dots provides an unique opportunity to optimize the electronic and optical properties of a semiconductor nanostructure. Size-selective luminescence, resonant Raman scattering, and time-resolved luminescence experiments provide insight into the exciton-LO-phonon and exciton-photon couplings in self-organized quantum dots. The impact of the structural details is analyzed based on eight-band k Á p model calculations.1 Introduction The interest in semiconductor quantum dots (QD's) results foremost from the modification of the electronic eigenstate spectrum [1]. The three-dimensional confinement leads to a discrete density of states drastically narrowing the thermal carrier distribution and limiting interaction processes [2]. The mesoscopic nature of QD's, which consist out of thousands of atoms, allows for a large diversity of structural realizations. The non-trivial relation between structural and electronic properties of QD's carries the potential to engineer the electronic/optical properties. In recent years it became clear that the detailed understanding of localized excitations in QD's requires to account for the interaction with lattice vibrations, i.e. phonons. The coupling to phonons determines, e.g., the line shape of transitions and the carrier dynamics. A detailed understanding of the effects of localizing a carrier/exciton in a QD on the interaction with phonons is essential, in particular for device applications.The observation of phonon-assisted transitions in optical spectra, i.e. phonon-assisted generation and recombination of excitons, or resonant Raman scattering provide information on the interaction with phonons. Experimentally, the main problem is the generally large inhomogeneous broadening of QD ensembles, typically exceeding the relevant phonon energies. Employing size-selective spectroscopy pronounced LO-phonon sidebands have been identified for almost spherical, unstrained II-VI QD's [3][4][5][6][7]. In the adiabatic approximation, the coupling strength is usually represented by the dimensionless Huang-Rhys factor [8] and can be directly estimated from the intensity ratios of different order phonon processes. Values of the order of unity have been reported for the polar exciton-LO-phonon coupling. The Fraehlich coupling of the exciton to a LO-phonon is proportional to the local charge

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Raman study of interface modes subjected to strain in InAs/GaAs self-assembled quantum dots

Cited by 56 publications

References 18 publications

Effects of annealing on electrical and optical properties of a multilayer InAs/GaAs quantum dots system

Effects of annealing on electrical and optical properties of a multilayer InAs/GaAs quantum dots system

Optophononics with coupled quantum dots

Exciton–LO‐phonon coupling in self‐organized InAs/GaAs quantum dots

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