Photoluminescence from a single GaAs/AlGaAs quantum dot

Brunner, K.; Bockelmann, Ulrich; Abstreiter, G.; Walther, M.; Böhm, G.; Tränkle, G.; Weimann, G.

doi:10.1103/physrevlett.69.3216

Cited by 313 publications

(147 citation statements)

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“…10 In the present work we observe clear phonon suppression in n-type quasi 0D dots ͑i.e., Landau quantized rather than spatially quantized͒ by a time-resolved intraband absorption measurement. This provides unambiguous evidence for the phonon bottleneck effect independently of arguments concerning which processes dominate in the interband photoluminescence measurements in dots [3][4][5][6][9][10][11][12] and quasi dots 13 such as electron-hole scattering. Further, because of the very clean model system ͑much sharper interfaces and no wetting layer, etc.͒, the interpretation is not complicated by detailed questions about different growth techniques and the quality of different dot sample structures.…”

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confidence: 89%

“…Recently much work has been carried out on the so-called ''phonon bottleneck'' that has been claimed to inhibit the cooling of carriers in quantum dots when the level separation is not equal to the phonon energy. [2][3][4][5][6] However, partly as a result of different groups using different growth techniques for interband photoluminescence samples and partly on fundamental grounds, this is controversial and is the subject of much debate. [7][8][9][10][11][12] Indeed several mechanisms have been proposed that may bypass the bottleneck, such as multiphonon scattering, 7 Auger processes, 8 excitonic effects, 9 and defect related processes.…”

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confidence: 99%

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Suppression of LO phonon scattering in Landau quantized quantum dots

et al. 1999

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Picosecond time-resolved far-infrared measurements are presented of the scattering between conductionband states in a doped quasi quantum dot. These states are created by the application of a magnetic field along the growth direction of an InAs/AlSb quantum well. A clear suppression of the cooling rate is seen, from 10 12 s Ϫ1 when the level spacing is equal to the phonon energy, to 10 10 s Ϫ1 away from this resonance, and thus the results provide unambiguous evidence for the phonon bottleneck. Furthermore, the lifetimes had only weak dependence on temperature between 4 and 80 K. ͓S0163-1829͑99͒50612-7͔Electronic lifetimes of two-dimensional ͑2D͒ systems in magnetic fields are of fundamental interest in part because the quantization effect of the magnetic field mimics the effect of a quantum dot potential with an easily variable degree of confinement. 1 The magnetic field perpendicular to the layers forces the electrons into confined orbits and the density of states becomes a ladder of broadened ␦ functions similar to that of a quantum dot. Recently much work has been carried out on the so-called ''phonon bottleneck'' that has been claimed to inhibit the cooling of carriers in quantum dots when the level separation is not equal to the phonon energy. [2][3][4][5][6] However, partly as a result of different groups using different growth techniques for interband photoluminescence samples and partly on fundamental grounds, this is controversial and is the subject of much debate. 7-12 Indeed several mechanisms have been proposed that may bypass the bottleneck, such as multiphonon scattering, 7 Auger processes, 8 excitonic effects, 9 and defect related processes. 10 In the present work we observe clear phonon suppression in n-type quasi 0D dots ͑i.e., Landau quantized rather than spatially quantized͒ by a time-resolved intraband absorption measurement. This provides unambiguous evidence for the phonon bottleneck effect independently of arguments concerning which processes dominate in the interband photoluminescence measurements in dots 3-6,9-12 and quasi dots 13 such as electron-hole scattering. Further, because of the very clean model system ͑much sharper interfaces and no wetting layer, etc.͒, the interpretation is not complicated by detailed questions about different growth techniques and the quality of different dot sample structures. The results should assist in the understanding of which aspect of these processes is fundamental and which is dependent on sample structure.Resonant absorption of longitudinal optic ͑LO͒ phonons causes a variety of transport properties to oscillate with applied magnetic field, such as the magnetoresistance. 14 Resonant phonon scattering occurs whenwhere ប LO is the LO phonon energy, ប c ϭបeB/m* is the cyclotron energy, and ⌬l is an integer. At these resonances the LO phonon absorption/emission probability is strongly enhanced giving rise to large changes in the electron energy relaxation lifetime. 15,16 In the present work we have used the pump-probe technique, with cyclotron resonan...

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Suppression of LO phonon scattering in Landau quantized quantum dots

et al. 1999

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“…By confining the motion of carriers in one, two or all three spatial dimensions, quantum wells (QWs), quantum wires (QWRs) and Quantum Dots (QDs) have been realized on planar substrates and studied in great detail over the past decades. In the field of optically active QWs and QDs several key experiments have been performed, including for example the isolation of individual "natural", interface fluctuation QDs in a disordered QW [1], bright, electrically driven single photon emission [2] or the creation of "artificial" molecules with tunable bonds [3]. A central goal in the active field of fundamental and applied research are semiconductor nanowires (NW).…”

Section: Introductionmentioning

confidence: 99%

Radio frequency occupancy state control of a single nanowire quantum dot

Weiß¹,

Schülein²,

Kinzel³

et al. 2014

J. Phys. D: Appl. Phys.

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Abstract.The excitonic occupancy state of a single, nanowire-based, heterostructure quantum dot is dynamically programmed by a surface acoustic wave. The quantum dot is formed by an interface or thickness fluctuation of a GaAs QW embedded in a AlGaAs shell of a GaAs − AlGaAs core-shell nanowire. As we tune the time at which carriers are photogenerated during the acoustic cycle, we find pronounced intensity oscillations of neutral and negatively charged excitons. At high acoustic power levels these oscillations become anticorrelated which enables direct acoustic programming of the dot's charge configuration, emission intensity and emission wavelength. Numerical simulations confirm that the observed modulations arise from acoustically controlled modulations of the electron and electron-hole-pair concentrations at the position of the quantum dot.

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“…Similarly, the optical excitation of a single quantum dot ͑QD͒ results in optical spectra reminiscent of atomic transitions with sharp and spectrally narrow lines. [3][4][5][6][7] The understanding of the complex optical spectra from single dots and their dependence on photoexcitation intensity is, however, still quite poor. The atomiclike lines in the spectra were found to exhibit intriguing red-and blue-shifts, and new features are seen to appear and disappear depending on the number of injected electronhole pairs.…”

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confidence: 99%