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Breakdown of Rotational Symmetry at Semiconductor Interfaces: a Microscopic Description of Valence Subband Mixing

100%

Cortez S., Krebs O., Voisin P.

Acta Physica Polonica A

2000

vol. 98

issue 3

303-323

The recently discovered in-plane optical anisotropy of [001]-grown quantum wells offers a new theoretical and experimental insight into the electronic properties of semiconductor interfaces. We first discuss the coupling of X and Y valence bands due to the breakdown of rotation inversion symmetry at a semiconductor hetero-interface, with special attention to its dependence on effective parameters such as the valence band offset. The intracell localization of Bloch functions is explained from simple theoretical arguments and evaluated numerically from a pseudo-potential microscopic model. The role of envelope functions is then considered, and we discuss the specific case of non-common atom interfaces. Experimental results and applications to interface characterization are presented. These calculations give a microscopic justification, and establish the limits of the heuristic "H_{BF}" model.

Optical Orientation of Trions in Charge-Tunable InAs/GaAs Quantum Dots

64%

Laurent S., Eble B., Krebs O., Lemaître A., Urbaszek B., Marie X., Amand T., Voisin P.

Acta Physica Polonica A

2004

vol. 106

issue 2

185-192

We report on optical orientation of excitons and trions (singly charged exciton) in individual charge-tunable self-assembled InAs/GaAs quantum dots. When the number of electrons varies from 0 to 2, the trion photoluminescence under quasi-resonant excitation gets progressively polarized from zero to ≈100%. We discuss this behavior as the efficient quenching of exciton spin quantum beats in anisotropic quantum dots due to the trion formation. This result indicates a long hole-spin relaxation time larger than the radiative lifetime, confirmed by time-resolved photoluminescence measurements carried out on a quantum dots ensemble.

Influence of an Electric Field on Fine Properties of III-V and II-VI Quantum Dots Systems

64%

Kowalik K., Krebs O., Kudelski A., Golnik A., Lemaître A., Senellart P., Karczewski G., Kossut J., Gaj J., Voisin P.

Acta Physica Polonica A

2004

vol. 106

issue 2

177-184

We investigate the influence of an electric field on the optical properties of single quantum dots. For sample made of III-V compounds micron-size electro-optical structures were produced in order to apply an electric field in the dot plane. For several individual dots lines significant variations of the anisotropic exchange splitting with the field were observed. On sample made of II-VI compounds we demonstrate the influence of electric field fluctuations on the luminescence of a single quantum dot.

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3 Acta Physica Polonica A

2 2004

1 2000

3 Krebs O.

3 Voisin P.

2 Lemaître A.

1 Amand T.

1 Cortez S.

1 Eble B.

1 Gaj J.

1 Golnik A.

1 Karczewski G.

1 Kossut J.

1 Kowalik K.

1 Kudelski A.

1 Laurent S.

1 Marie X.

1 Senellart P.

1 Urbaszek B.

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Breakdown of Rotational Symmetry at Semiconductor Interfaces: a Microscopic Description of Valence Subband Mixing

Optical Orientation of Trions in Charge-Tunable InAs/GaAs Quantum Dots

Influence of an Electric Field on Fine Properties of III-V and II-VI Quantum Dots Systems