Optical investigations on single vertically coupled InP/GaInP quantum dot pairs

Kessler, Christian; Reischle, M.; Roßbach, R.; Koroknay, Elisabeth; Jetter, Michael; Michler, Peter

doi:10.1002/pssb.201200004

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…3(e,f). We ascribe this to Pauli blockade: 42 the PLE absorption in QD B2 is observed only when QD A2 is empty, by contrast the PL from QD B2 can only be observed when QD A2 is occupied with an exciton, preventing further exciton tunneling from QD B2 as well as shifting the ground state energy of QD B2.…”

Section: Qd Bmentioning

confidence: 96%

Vanishing electrongfactor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots

et al. 2016

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GaAs/AlGaAs quantum dots grown by in situ droplet etching and nanohole infilling offer a combination of strong charge confinement, optical efficiency, and spatial symmetry required for polarization entanglement and spin-photon interface. Here we study spin properties of such dots. We find nearly vanishing electron g-factor (g e < 0.05), providing a route for electrically driven spin control schemes. Optical manipulation of the nuclear spin environment is demonstrated with nuclear spin polarization up to 60% achieved. NMR spectroscopy reveals the structure of two types of quantum dots and yields the small magnitude of residual strain ε b < 0.02% which nevertheless leads to long nuclear spin lifetimes exceeding 1000 s. The stability of the nuclear spin environment is advantageous for applications in quantum information processing.Central spin in semiconductor quantum dots is a prime candidate for applications in quantum information technologies. 1,2 It is relatively isolated from the solid state effects and at the same time is accessible for coherent manipulation and can be interfaced optically. The coherence in this system is mainly limited by the hyperfine coupling with the nuclear spin bath. 3,4 Single spin qubit manipulation in these structures, therefore, demands an auxiliary control over nuclear spin environment. Such control can be realized by maximizing polarization of 10 4 − 10 5 nuclei in a single quantum dot, 5-7 enabling the formation of well-defined nuclear spin states and in effect reducing the influence of the nuclear field fluctuations. 8,9 Central spin manipulation in semiconductor quantum dot (QD) system using resonant ultrafast optical pulses 10,11 has been demonstrated but scalability in such schemes is challenging. An alternative approach is to induce controlled spin rotation by manipulating the coupling to the external magnetic field. 12 This can be achieved by electrical modulation of the g-factor. However, such scheme critically depends on the ability to change the sign of g, thus requiring quantum dots with close to zero electron or hole g-factor. 13,14 Self-assembled InGaAs/GaAs QD has been the primary system of choice for spin studies over the last two decades, as quantum confinement in monolayer-fluctuation GaAs/AlGaAs dots is too weak. Only recently the potential of droplet epitaxial (DE) grown GaAs QDs has been identified. [15][16][17] In particular nanohole-filled droplet epitaxial (NFDE) dots formed by in situ etching and nanohole infilling 18 provide confinement and excellent optical efficiency, while on the other hand exhibiting high symmetry not achievable previously in self-assembled dots. 19 Such unique com-1 arXiv:1507.06553v1 [cond-mat.mes-hall]

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Section: Qd Bmentioning

confidence: 96%

Vanishing electrongfactor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots

et al. 2016

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“…The simplest and most investigated QDM is coupled QDs 6. QD pairs can be conveniently fabricated by stacking vertical QD pairs 7. In order to fabricate quantum gates in quantum computing, lateral coupled QDs are required.…”

Section: Introductionmentioning

confidence: 99%

Influence of Ga coverage on the sizes of GaAs quantum dash pairs grown by high temperature droplet epitaxy

Wang

et al. 2012

Physica Rapid Research Ltrs

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We investigate the formation of GaAs quantum dash pairs with different coverages by droplet epitaxy. The GaAs quantum dash pairs of various sizes are fabricated by high temperature droplet epitaxy. Dual‐sized quantum dash pairs are observed along $[01\bar 1]$ orientation. Depending on the Ga cov‐ erage, the width of the quantum dash pairs can be tuned from ∼100 nm to ∼300 nm while keeping the height in the range of 4 nm to 10 nm. The coverage dependence of quantum dash pairs is also confirmed with photoluminescence measurement. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…It was mounted on a stage with manual and piezo-controlled movement, providing spatial resolution of the order of 10 nm. The sample was mounted in a continuousflow microscopy cryostat (18) with short working distance and providing temperatures down to 5 K. The cryostat was put on a motorized stage with the movement precision below 100 nm, which together with piezo-controlled microscope objective provided accurate alignment, required for single dot study. Emission from a sample was collected by the same microscope objective (17), sent through a longpass filter (22) removing the laser line, and focused by an achromatic doublet lens (23) on an entrance slit of a monochromator (24) with focal length of 1000 mm.…”

Section: Methodsmentioning

confidence: 99%

“…For single QD study, PLE has been used for a long time, identifying the energy structure of confined levels [10][11][12][13][14], demonstrating phonon-enhanced carrier relaxation [15], showing existence of continuum of states at the energies below the wetting layer ground state where only sharp absorption lines are usually expected [16], evidencing coupling between single QDs [17][18][19] or making possible coherent control of a single quantum dot [20]. However, these studies have been limited to dots emitting below 1 µm, primarily.…”

Section: Introductionmentioning

confidence: 99%

Single dot photoluminescence excitation spectroscopy in the telecommunication spectral range

Podemski

Maryński

Wyborski

et al. 2019

Journal of Luminescence

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Single dot photoluminescence excitation spectroscopy provides an insight into energy structure of individual quantum dots, energy transfer processes within and between the dots and their surroundings. The access to single dot energy structure is vital for further development of telecom-based quantum emitters, like single photon sources or entangled pair of photons. However, application of single dot photoluminescence excitation spectroscopy is limited mainly to dots emitting below 1 µm, while nanostructures optically active in the telecommunication windows of 1.3 and 1.55 µm are of particular interest, as they correspond to the desirable wavelengths in nanophotonic applications. This report presents an approach to photoluminescence excitation spectroscopy covering this application-relevant spectral range on single dot level. Experimental details are discussed, including issues related to the tunable excitation source and its spectral filtering, and illustrated with examples of photoluminescence excitation spectroscopy results from single quantum dots emitting in both the 1.3 and 1.55 µm spectral ranges.

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Optical investigations on single vertically coupled InP/GaInP quantum dot pairs

Cited by 5 publications

References 18 publications

Vanishing electrongfactor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots

Vanishing electrongfactor and long-lived nuclear spin polarization in weakly strained nanohole-filled GaAs/AlGaAs quantum dots

Influence of Ga coverage on the sizes of GaAs quantum dash pairs grown by high temperature droplet epitaxy

Single dot photoluminescence excitation spectroscopy in the telecommunication spectral range

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