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Ropers, Claus; Wenderoth, M.; Winking, L.; Reusch, T. C. G.; Erdmann, Matthias; Ulbrich, R. G.; Grochol, M.; Grosse, Frank; Zimmermann, R.; Malzer, S.; Döhler, G. H.

doi:10.1103/physrevb.75.115317

Cited by 11 publications

(18 citation statements)

References 31 publications

(15 reference statements)

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“…35 It is known that a change of effective mass within the quantum-well plane could further increase the exciton binding energies. 36 However, the in-plane effective masses are not expected to change so significantly in wurtzite GaAs. 33 Most importantly, the presumably type-II nature of the transition actually leads to a separation of electrons and holes, thus diminishing the Coulomb interaction between the carriers.…”

Section: B Wurtzite/zinc-blende Gaas Band Offsetsmentioning

confidence: 99%

Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures

et al. 2011

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A method for the direct correlation at the nanoscale of structural and optical properties of single GaAs nanowires is reported. Nanowires consisting of 100% wurtzite and nanowires presenting zinc-blende/wurtzite polytypism are investigated by photoluminescence spectroscopy and transmission electron microscopy. The photoluminescence of wurtzite GaAs is consistent with a band gap of 1.5 eV. In the polytypic nanowires, it is shown that the regions that are predominantly composed of either zinc-blende or wurtzite phase show photoluminescence emission close to the bulk GaAs band gap, while regions composed of a nonperiodic superlattice of wurtzite and zinc-blende phases exhibit a redshift of the photoluminescence spectra as low as 1.455 eV. The dimensions of the quantum heterostructures are correlated with the light emission, allowing us to determine the band alignment between these two crystalline phases. Our first-principles electronic structure calculations within density functional theory, employing a hybrid-exchange functional, predict band offsets and effective masses in good agreement with experimental results.

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Section: B Wurtzite/zinc-blende Gaas Band Offsetsmentioning

confidence: 99%

Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures

et al. 2011

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“…In general thick QWs are the less sensitive to interface roughness, and conversely predicted/found to be, at cryogenic temperatures, extremely responsive to unintentional impurities (which can be very low in MBE), due to the aforementioned exciton interaction with the effective "atomic-scale roughness" associated with impurity centre [14,15,16,17,18].…”

Section: Introductionmentioning

confidence: 97%

“…As schematically depicted in Fig. 1, the excitonic wavefunction is interacting with a number of features present into a QW and its barriers, which in turn affect the long and short range potential template experienced by the exciton, and so its emission energy: interface roughness, alloy disorder in the barrier (an alloy is never a perfectly random structure, resulting in a local modulation of the alloy composition), and the presence of impurities in the barrier and QW materials [15,16,17]. Other parameters/variables not shown in Fig.1 also play a role, e.g.…”

Section: Introductionmentioning

confidence: 99%

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AlGaAs/GaAs/AlGaAs quantum wells as a sensitive tool for the MOVPE reactor environment

Dimastrodonato

Mereni

Young

et al. 2010

Journal of Crystal Growth

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We present in this work a simple Quantum Well (QW) structure consisting of GaAs wells with AlGaAs barriers as a probe for measuring the performance of arsine purifiers within a MetalOrganic Vapour Phase Epitaxy system.Comparisons between two different commercially available purifiers are based on the analysis of low temperature photoluminescence emission spectra from thick QWs, grown on GaAs substrates misoriented slightly from (100). Neutral excitons emitted from these structures show extremely narrow linewidths, comparable to those which can be obtained by Molecular Beam Epitaxy in an ultra-high vacuum environment, suggesting that purifications well below the 1ppb level are needed to achieve high quality quantum well growth.

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“…Furthermore, the reduced values of the measured diamagnetic shift could not be explained only by the influence of the disorder. The giant magnetoresistance as a combined effect of both: the disorder and the magnetic field, has been observed in coupled QWs [6].In this paper, a potential correlation function deduced from experiment [7] is taken as input to generate new electron and hole lateral disorder potentials. The exciton Schrödinger equation is solved exactly including a perpendicular magnetic field.…”

mentioning

confidence: 99%

Exciton diamagnetic shift in realistic quantum wells

Grochol

Grosse

Zimmermann

2006

Phys. Status Solidi (c)

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Exciton absorption spectra, diamagnetic shifts and localization of wave functions in realistic AlGaAs quantum wells with disorder are investigated. Two effective electron masses are chosen, bulk and enhanced due to confinement, in order to show the mass influence on the exciton properties. Whereas the absorption spectra and the localization of the wave function are modified only slightly, the diamagnetic shift turns out to be very sensitive. It is also shown that the average diamagnetic shift increases with the exciton energy.Semiconductor quantum wells (QW) have been a subject of intensive study for many years. The reduction in size of active layers in these structures leads to a stronger influence of imperfections, specifically well width fluctuations. Near band-edge optical properties of semiconductors are dominated by the excitons. Their sensitivity to disorder and especially the localization of the exciton wave function gives us the possibility to investigate certain aspects of the underlying structure at the length of the exciton Bohr radius (see Ref.[1] and references therein).Up to now, numerical simulations of the exciton properties were performed using either potentials generated artificially or coming from simple growth simulations [2]. Good agreement between theory and experiment could be achieved if two basic parameters of the disorder in the confinement potential (variance and correlation length) were adjusted (see e.g. [3]). Recently, the previously used factorization of the total wave function valid for weak disorder was tested and some differences in the absorption spectra and the wave function properties were revealed [4]. It has also been confirmed both theoretically [4] and experimentally [5], that the diamagnetic shift varies in a non-monotonic way among different localized excitons. Furthermore, the reduced values of the measured diamagnetic shift could not be explained only by the influence of the disorder. The giant magnetoresistance as a combined effect of both: the disorder and the magnetic field, has been observed in coupled QWs [6].In this paper, a potential correlation function deduced from experiment [7] is taken as input to generate new electron and hole lateral disorder potentials. The exciton Schrödinger equation is solved exactly including a perpendicular magnetic field. Absorption spectra and diamagnetic shifts are calculated. Two values for the electron effective mass are adopted: the bulk one (m . It is shown that the diamagnetic shift is very sensitive to the choice of the effective electron mass, unlike absorption spectra, binding energies, or localization of the wave function.The single sublevel approximation with the confinement wave functions for electron u e (z e ) and hole u h (z h ) of the realistic quantum well is assumed [7]. Then, the in-plane Hamiltonian for excitons in a disordered QW in effective mass approximation under applied perpendicular magnetic field B in the Coulomb

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Atomic scale structure and optical emission ofAlxGa1−xAs∕GaAsquantu

Cited by 11 publications

References 31 publications

Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures

Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures

AlGaAs/GaAs/AlGaAs quantum wells as a sensitive tool for the MOVPE reactor environment

Exciton diamagnetic shift in realistic quantum wells

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