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- Karlsson, Fredrik, 1974-, et al.
(författare)
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Optical polarization anisotropy and hole states in pyramidal quantum dots
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89, s. 251113-
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Tidskriftsartikel (refereegranskat)abstract
- The authors present a polarization-resolved photoluminescence study of single semiconductor quantum dots (QDs) interconnected to quantum wires, measured both in a top geometry, and in a less conventional cleaved-edge geometry. Strong polarization anisotropy is revealed for all observed transitions, and it is deduced that closely spaced QD hole states exhibit nearly pure heavy-or light-hole character. These effects are attributed to the large aspect ratio of the dot shape
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| 5. |
- Malko, A., et al.
(författare)
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Single-photon emission from pyramidal quantum dots : The impact of hole thermalization on photon emission statistics
- 2005
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 72, s. 195332-
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Tidskriftsartikel (refereegranskat)abstract
- We report an experimental study of the emission statistics of excitonic complexes from a single quantum dot and their temperature dependence. The single photon emission from the exciton ground state is shown to persist up to 80 K. The deterioration of single photon statistics is attributed to new biexciton emissions, which emerge in the vicinity of the main single-exciton peak at rising temperatures. We identify these biexcitonic states as being formed by either one hole or two holes occupying excited states and analyze their specific polarization and power-dependent signature.
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- Troncale, V., et al.
(författare)
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Excited excitonic states observed in semiconductor quantum dots using polarization resolved optical spectroscopy
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101, s. 081703-
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Tidskriftsartikel (refereegranskat)abstract
- We present results on the polarization-resolved photoluminescence emitted from InGaAs/AlGaAs single quantum dots (QDs) grown in inverted tetrahedral pyramids. The emitted light was detected for two mutually perpendicular linear polarization directions in the less conventional cleaved-edge geometry, in addition to the standard top-emission geometry. Whereas the in-plane linear polarization was isotropic, as a consequence of the high symmetry of the system, we found a strong polarization anisotropy of the edge-emitted light revealing QD states of predominantly heavy- or light-hole character. By temperature control of the charge state, several neutral and charged light-hole like exciton complexes were identified. In particular, a biexciton showing a twofold radiative recombination path, leading to two nearly perpendicularly polarized emission multiplets, was identified. These results are also of technological relevance for any design of optoelectronic QD-integrated devices
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- Malko, A., et al.
(författare)
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Optimization of the efficiency of single-photon sources based on quantum dots under optical excitation
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 88, s. 081905-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate efficient, regulated single-photon operation from site-controlled InGaAs quantum dots (QDs) grown on a prepatterned substrate. Under nonresonant optical excitation, carriers trapped at structural or compositional defects of the adjacent nanostructures led to a degradation of the single-photon statistics from a QD. When the QD was excited quasiresonantly, single photons were emitted and a nearly complete suppression of multiphoton emission was achieved, making these QDs promising candidates for effective solid-state single-photon sources
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