Giant optical anisotropy in a single InAs quantum dot in a very dilute quantum-dot ensemble

Favero, Iván; Cassabois, Guillaume; Janković, Aleksandar; Ferreira, Robson; Darson, David; Voisin, Christophe; Delalande, Claude; Roussignol, Philippe; Badolato, Antonio; Petroff, P. M.; Gérard, Jean‐Michel

doi:10.1063/1.1854733

Cited by 38 publications

(24 citation statements)

References 23 publications

(49 reference statements)

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“…We also calculate alloy dots of the same geometry but with different alloy distributions [13] and find that the alloy distribution does not significantly change the values of and . In contrast, , , and the polarization angle at p ¼ 0 change dramatically from dot to dot, in agreement with recent experiments [21]. However, in all cases, the behaviors of the FSS and polarization angle under stress are in excellent agreement with our theoretical predictions.…”

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confidence: 92%

Exciton Polarization, Fine-Structure Splitting, and the Asymmetry of Quantum Dots under Uniaxial Stress

et al. 2011

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We derive a general relation between the fine-structure splitting (FSS) and the exciton polarization angle of self-assembled quantum dots under uniaxial stress. We show that the FSS lower bound under external stress can be predicted by the exciton polarization angle and FSS under zero stress. The critical stress can also be determined by monitoring the change in exciton polarization angle. We confirm the theory by performing atomistic pseudopotential calculations for the InAs/GaAs quantum dots. The work provides deep insight into the dot asymmetry and their optical properties and a useful guide in selecting quantum dots with the smallest FSS, which are crucial in entangled photon source applications.

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confidence: 92%

Exciton Polarization, Fine-Structure Splitting, and the Asymmetry of Quantum Dots under Uniaxial Stress

et al. 2011

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“…This is due to the strong difference between heavy-and light-hole effective masses in these materials. Large polarization degree has only been observed in strongly elongated InAs QDs [53], in CdTe QDs grown on vicinal substrates [54] or in quantum wires [55], that is to say when the confinement is highly anisotropic and mixes valence bands. In nitridebased heterostructures, A and B valence bands have identical on-axis effective masses, i.e.…”

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confidence: 99%

Polarized emission from GaN/AlN quantum dots: Single-dot spectroscopy and symmetry-based theory

et al. 2008

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We report micro-photoluminescence studies of single GaN/AlN quantum dots grown along the (0001) crystal axis by molecular beam epitaxy on Si(111) substrates. The emission lines exhibit a linear polarization along the growth plane, but with varying magnitudes of the polarization degree and with principal polarization axes that do not necessarily correspond to crystallographic directions. Moreover, we could not observe any splitting of polarized emission lines, at least within the spectral resolution of our setup (1 meV). We propose a model based on the joint effects of electron-hole exchange interaction and in-plane anisotropy of strain and/or quantum dot shape, in order to explain the quantitative differences between our observations and those previously reported on, e.g. CdTe-or InAs-based quantum dots.

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“…2 In the absence of magnetic field, the emission from quantum dots is often not isotropic with respect to its polarization direction. 3,4 Strong biaxial strain suppresses light-hole components in the valence-band states, leaving mostly heavyhole components and resulting in in-plane polarized emission from the interband transitions. 5,6 It has been shown that the linear polarization of the interband transitions in a selfassembled quantum dot originates from its shape anisotropy.…”

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Optical characterization of structure for semiconductor quantum dots

Sheng

2008

Phys. Rev. B

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Linear polarization of the multiexciton emission from self-assembled quantum dots is investigated by using an empirical tight-binding method. The polarization of the primary interband transition is shown to have a quadratic dependence on the lateral aspect ratio of the structures and is insensitive to both the excitonic and random intermixing effects, which make it an appropriate tool for structure characterization. The ground-state transitions in the emission spectra of multiexciton complexes are found to exhibit very different polarization from the primary interband transition, which we attribute to different component profiles in the excited valence-band states.Semiconductor self-assembled quantum dots, sometimes called artificial atoms, 1 are three-dimensional nanostructures in which carriers are confined along the three dimensions of space by the band gap difference between the dot and barrier materials. The electronic and optical properties of these nanoscale systems are affected by the strong influence of the low symmetry of the confined nanostructures and the strain due to the lattice mismatch between the different materials. Unlike natural atoms, self-assembled quantum dots take various shapes that can be either symmetric or asymmetric. Ascertaining the shape of quantum dots and other related structural parameters is of primary importance for both fundamental and practical reasons. 2 In the absence of magnetic field, the emission from quantum dots is often not isotropic with respect to its polarization direction. 3,4 Strong biaxial strain suppresses light-hole components in the valence-band states, leaving mostly heavyhole components and resulting in in-plane polarized emission from the interband transitions. 5,6 It has been shown that the linear polarization of the interband transitions in a selfassembled quantum dot originates from its shape anisotropy. 7 Due to very little difference in the dielectric constants between the quantum dot and barrier materials, the local field or depolarization effect is believed to contribute only a small portion of the overall linear polarization of the emission.Optical spectroscopy has been shown to be an appropriate tool for probing many electronic properties of quantum dots, such as the shell structure of electronic states. 8 However, for self-assembled quantum dots, a direct manifestation of geometrical anisotropy by optical spectroscopy has yet been well established, which we believe is due to the lack of an applicable theory that bridges these two aspects. In the present work, we will explore the possibility of optical characterization of structure for semiconductor self-assembled quantum dots. The proposed scheme is based on a quantitative relation established between the optical and shape anisotropies by an empirical tight-binding approach. 9,10The model system is an InAs/ GaAs quantum dot which is elongated along the ͓110͔ direction. It has a variable lateral aspect ratio ␤ = d x / d y where d x ͑=d͒ and d y are the dimensions along the long ͑x = ͓110͔͒ and sho...

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Giant optical anisotropy in a single InAs quantum dot in a very dilute quantum-dot ensemble

Cited by 38 publications

References 23 publications

Exciton Polarization, Fine-Structure Splitting, and the Asymmetry of Quantum Dots under Uniaxial Stress

Exciton Polarization, Fine-Structure Splitting, and the Asymmetry of Quantum Dots under Uniaxial Stress

Polarized emission from GaN/AlN quantum dots: Single-dot spectroscopy and symmetry-based theory

Optical characterization of structure for semiconductor quantum dots

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