| 1. |
- Marangolo, M, et al.
(författare)
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Magnetism of the Fe/ZnSe(001) interface
- 2002
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 88:21, s. 217202-
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Tidskriftsartikel (refereegranskat)abstract
- The magnetism of epitaxial ultrathin films of Fe on ZnSe(001) has been investigated by x-ray magnetic circular dichroism down to the submonolayer regime. In contrast to other metallic ferromagnet/semiconductor interfaces, no reduction of the Fe magnetic moment was found at the Fe/ZnSe(001) interface. Furthermore, a significant enhancement of the Fe magnetic moment compared to the bulk value was observed for coverages up to one monolayer in agreement with theoretical predictions. We also demonstrate that the magnetic properties of the Fe/ZnSe(001) interface remain stable against thermal annealing up to 300 degrees C, a prerequisite for the future development of efficient spintronics devices.
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| 2. |
- Pettersson, H., et al.
(författare)
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Excitons in self-assembled quantum ring-like structures
- 2000
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Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - Amsterdam : Elsevier. - 1386-9477 .- 1873-1759. ; 6:1-4, s. 510-513
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Tidskriftsartikel (refereegranskat)abstract
- A remarkable morphological change of self-assembled InAs quantum dots takes place during growth if a pause is introduced after overgrowing the dots with a few nm of GaAs. Atomic force microscopy indicates that the shape of the dots changes lens-like to ring-like. We report here the results of capacitance and interband transmission experiments on such ring-like structures embedded in a GaAs matrix. In particular, we compare the electronic properties of conventional dots with those of the rings. Significant changes are found which qualitatively support a quantum ring model. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 3. |
- Karlsson, Fredrik, 1974-, et al.
(författare)
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Carrier diffusion in the barrier enabling formation of charged excitons in InAs/GaAs quantum dots
- 2001
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Ingår i: XXX International School on the Physics of Semiconducting Compounds,2001. - : Polish Academy of Sciences, Institute of Physics. ; , s. 387-395
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Konferensbidrag (refereegranskat)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled quantum dots are very sensitive to the experimental conditions, such as excitation energy and crystal temperature. A qualitative explanation is given in terms of the effective diffusion of the photogenerated carriers, determined by the experimental conditions, which influence the capture probability and hence also the charge state of the quantum dots. This is proposed as a new tool to populate quantum dots with extra electrons in order to study phenomena involving charged excitons.
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| 4. |
- Karlsson, Fredrik, 1974-, et al.
(författare)
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Effective tuning of the charge-state of single In(Ga)As/GaAs quantum dots by below barrier band gap excitation
- 2003
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 532-535, s. 843-847
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Tidskriftsartikel (refereegranskat)abstract
- The existence of a well-defined threshold energy, crucial for the charging of quantum dots (QDs), positioned between the barrier band gap and the wetting layer ground state is demonstrated. Optical excitation with energies above this threshold populates the QDs with extra electrons. The origin of the threshold is discussed in terms of acceptors in the GaAs barrier. ⌐ 2003 Elsevier Science B.V. All rights reserved.
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| 5. |
- Karlsson, Fredrik, 1974-, et al.
(författare)
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Optical charging of self-assembled InAs/GaAs quantum dots
- 2002
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Ingår i: Physica scripta. T. - 0281-1847. ; 101, s. 140-142
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled quantum dots are very sensitive to the experimental conditions, such as excitation energy and crystal temperature. A qualitative explanation is given in terms of the effective diffusion of the photogenerated carriers, determined by the experimental conditions, which influence the capture probability and hence also the charge state of the quantum dots. This is proposed as an effective tool to populate single quantum dots with extra electrons, by purely optical means, in order to study phenomena involving charged excitons.
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| 6. |
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| 7. |
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| 8. |
- Karlsson, Fredrik, 1974-, et al.
(författare)
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Temperature influence on optical charging of self-assembled InAs/GaAs semiconductor quantum dots
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:19, s. 2952-2954
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled InAs/GaAs quantum dots are very sensitive to excitation energy and crystal temperature. This is qualitatively explained in terms of the effective diffusivity of photogenerated particles, which affects the capture probability of the quantum dot. As a consequence, this opens the possibility of controlling the average number of excess electrons in the quantum dot by optical means. This technique may be used as a simple tool to create and study charged exciton complexes without any specially fabricated samples. ⌐ 2001 American Institute of Physics.
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| 9. |
- Karlsson, Fredrik, 1974-, et al.
(författare)
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The influence of carrier diffusion on the formation of charged excitons in InAs/GaAs quantum dots
- 2002
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Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - 1386-9477 .- 1873-1759. ; 13:2-4, s. 101-104
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled quantum dots are very sensitive to the excitation energy and crystal temperature. A qualitative explanation is given in terms of the effective diffusivity of the photogenerated carriers, determined by the experimental conditions, which influence the capture probability and hence also the charge state of the quantum dots (QDs). This is proposed as an effective tool to populate quantum dots with extra electrons in order to study phenomena involving charged excitons. ⌐ 2002 Elsevier Science B.V. All rights reserved.
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| 10. |
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