| 11. |
- Chen, Weimin, 1959-, et al.
(författare)
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Efficient spin depolarization in ZnCdSe spin detector : an important factor limiting optical spin injection efficiency in ZnMnSe/CdZnSe spin light-emitting structures
- 2004
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 5260-
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Tidskriftsartikel (refereegranskat)abstract
- Spin depolarization of a ZnCdSe quantum-well spin detector (SD) in ZnMnSe/ZnCdSe light-emitting quantum structures is investigated by cw and time-resolved optical orientation spectroscopy. It is shown that spin depolarization is governed by three distinct spin relaxation processes with the corresponding polarization decay times of 850, 30, and <10 ps. The dominant and the fastest process is attributed to spin relaxation accompanying energy relaxation of hot excitons (and hot carriers) within the SD, providing evidence that it can be an important source of spin loss, leading to the observed limited efficiency of optical spin injection in the structures.
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| 12. |
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| 13. |
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| 14. |
- Terentev, Ya. V., et al.
(författare)
-
Semimagnetic ZnMnSe/CdSe Fractional Monolayer Superlattice as an Injector of Spin-Polarized Carriers
- 2002
-
Ingår i: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 229:2, s. 765-768
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Tidskriftsartikel (refereegranskat)abstract
- We report on effective injection of spin-oriented carriers from a semimagnetic semiconductor structure to a non-magnetic ZnCdSe/ZnSe quantum well (QW). A short-period ZnMnSe/CdSe fractional monolayer superlattice was used as a spin injector. The carriers are photo-generated in the semimagnetic region, spin-polarized via the effect of giant Zeeman splitting and then injected into the non-magnetic QW. The spin injection efficiency was estimated by circular polarization measurements of recombination emission from the QW. The maximal detected degree of the spin polarization is about 25%.
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| 15. |
- Toropov, A.A., et al.
(författare)
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Dynamics of excitons near the mobility edge in CdSe/ZnSe superlattices
- 2000
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Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 214, s. 806-809
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics properties of hot excitons near the effective excitonic mobility edge are investigated in a CdSe/ZnSe superlattice structure where thermalized luminescence of localized excitons is strongly suppressed due to tunneling towards the attached deeper ZnCdSe quantum well. Time-resolved selective-excitation luminescence measurements reveal a rather complicated relaxation behavior involving fast (20-30 ps) acoustical-phonon-assisted selective occupation of states located close to the mobility edge.
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| 16. |
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| 17. |
- Toropov, A.A., et al.
(författare)
-
Magneto-photoluminescence studies of diluted magnetic semiconductor type-II quantum wells ZnMnSe/ZnSSe
- 2003
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Ingår i: Proceedings of the International Conference on Superlattices, Nano-structures and Nano-devices ICSNN 2002 o-structures and Nano-devices ICSNN 2002. ; , s. 352-354
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Konferensbidrag (refereegranskat)abstract
- Magneto-photoluminescence (PL) has been studied in type II Zn1-xMnxSe/ZnSySe1-y multiple quantum wells (QWs) with the Mn content x between 0.03 and 0.15. Two PL lines are observed in the samples with x equal to 0.05 and 0.15. The lines are attributed to the excitons of two different types, coexisting in the QWs. At least one of them is associated with the formation of an exciton magnetic polaron. © 2002 Elsevier Science B.V. All rights reserved.
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| 18. |
- Toropov, A. A., et al.
(författare)
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ZnMnSe/ZnSSe Type-II semimagnetic superlattices : Growth and magnetoluminescence properties
- 2002
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Ingår i: Semiconductors (Woodbury, N.Y.). - : Pleiades Publishing Ltd. - 1063-7826 .- 1090-6479. ; 36:11, s. 1288-1293
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Tidskriftsartikel (refereegranskat)abstract
- A ZnSSe/ZnMnSe type-II semimagnetic superlattice was pseudomorphically grown via molecular beam epitaxy on a GaAs substrate. The superlattice-layer thicknesses and compositions were chosen so that compressive strains in the ZnMnSe layer compensated tensile strains in the ZnSSe layer. The photoluminescence spectra in an external magnetic field demonstrate the effect of giant Zeeman splitting of an exciton. Simulation of the luminescence-line shift in a magnetic field allowed us to determine more accurately the band offsets at the ZnSSe/ZnMnSe interface.
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| 19. |
- Buyanova, Irina, 1960-, et al.
(författare)
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Control of spin functionality in ZnMnSe-based structures : Spin switching versus spin alignment
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:11, s. 1700-
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Tidskriftsartikel (refereegranskat)abstract
- The ability of attaining desired spin functionality by adjusting structural design is demonstrated in diluted magnetic semiconductor (DMS) quantum structures based on II-VI semiconductors. The following spin enabling functions are achieved by tuning the ratio between the rates of exciton spin relaxation within the DMS and exciton escape from it to an adjacent nonmagnetic spin detector. Spin switching is realized when using a thin layer of Zn0.95Mn0.05Se as a spin manipulator and is attributed to a fast exciton escape from the DMS preceding the spin relaxation. Spin alignment is accomplished in tunneling structures where the presence of an energy barrier inserted between a spin manipulator (a DMS-based superlattice) and a spin detector ensures a slow escape rate from the DMS layer.
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| 20. |
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