| 31. |
|
|
| 32. |
- Chen, Weimin, 1959-, et al.
(författare)
-
Spin relaxation in InGaN/Ga(Mn)N quantum wells
- 2005
-
Ingår i: Bulletin of the American physical society. - 0003-0503. ; 50, s. 609-609
-
Tidskriftsartikel (refereegranskat)abstract
- Proc. 2005 APS March Meeting, March 21-25, 2005; Los Angeles, CA, USA
|
|
| 33. |
|
|
| 34. |
|
|
| 35. |
- Dagnelund, Daniel, 1980-, et al.
(författare)
-
Efficiency of optical spin injection and spin loss from a diluted magnetic semiconductor ZnMnSe to CdSe nonmagnetic quantum dots
- 2008
-
Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 77:3, s. 035437-
-
Tidskriftsartikel (refereegranskat)abstract
- Magneto-optical spectroscopy in combination with tunable laser spectroscopy is employed to study optical spin injection from a diluted magnetic semiconductor (DMS) ZnMnSe into nonmagnetic CdSe quantum dots (QDs). Observation of a DMS feature in the excitation spectra of the QD photoluminescence polarization provides clear evidence for optical spin-injection from the DMS to the QDs. By means of a rate equation analysis, the injected spin polarization is deduced to be about 32% at 5 T, decreasing from 100% before the injection. The observed spin loss is shown to occur during the spin injection process including crossing the heterointerfaces and energy relaxation within the QDs. © 2008 The American Physical Society.
|
|
| 36. |
|
|
| 37. |
- Dagnelund, Daniel, et al.
(författare)
-
Magneto-optical and tunable laser excitation spectroscopy of spin-injection and spin loss from Zn(Cd)MnSe diluted magnetic quantum well to CdSe non-magnetic quantum dots
- 2008
-
Konferensbidrag (refereegranskat)abstract
- Magneto-optical spectroscopy in combination with tunable laser spectroscopy is employed to study the effect of sample design on optical spin-injection efficiency from a Zn(Cd)MnSe diluted magnetic semiconductor (DMS) into non-magnetic CdSe quantum dots (QDs). Two samples with inverted growth sequence of the DMS and QD layers were grown for this purpose. Despite observation of clear evidence for exciton/carrier-injection from the DMS to the QDs in both structures, their spin-injection efficiency is markedly different. The structure grown with the QD layer topmost exhibits rather efficient spin-injection, while the structure grown with the DMS layer topmost does not show any sign of spin-injection. Even in the former case, the spin-polarization of the injected excitons/carriers is deduced to be about 32%, decreasing from 100% before the injection. The observed spin loss is shown to occur during the spin-injection across the heterointerfaces. © 2007 Elsevier B.V. All rights reserved.
|
|
| 38. |
- Dagnelund, Daniel, et al.
(författare)
-
Spin injection in a coupled system of a diluted magnetic semiconductor Zn0.80Mn0.20Se and self-assembled quantum dots of CdSe
- 2008
-
Ingår i: Proceedings of the 7th International Conference on Physics of Light-Matter Coupling in Nanostructures. - : Elsevier BV. ; , s. 615-619
-
Konferensbidrag (refereegranskat)abstract
- Spin injection processes from a Zn0.80Mn0.20Se diluted magnetic semiconductor (DMS) to adjacent self-assembled CdSe quantum dots (QDs) were investigated by cw and time-resolved magneto-optical spectroscopy in combination with tunable laser excitation. Direct experimental evidence for the spin injection was provided from the generation of the spin polarization in the QDs, which was opposite to their expected intrinsic polarization, by resonantly generating the spins in the DMS. The observed limited spin polarization generated by the spin injection, together with the sensitivity of the spin injection efficiency on structure design, indicates severe spin loss during the process and calls for further investigations to optimize spin injection efficiency in quantum structures. © 2007 Elsevier Ltd. All rights reserved.
|
|
| 39. |
- Furuta, T., et al.
(författare)
-
Spin-injection dynamics and effects of spin relaxation in self-assembled quantum dots of CdSe
- 2008
-
Ingår i: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 53, s. 163-166
-
Tidskriftsartikel (refereegranskat)abstract
- We study the spin injection dynamics and the effects of spin relaxation in self-assembled quantum dots (QDs) of CdSe coupled with a diluted magnetic semiconductor (DMS) layer of ZnMnSe, where spin-polarized excitons can be injected from the DMS into the QDs because of the potential difference. The degree of circular polarization, $P$, of excitonic photoluminescence (PL) at 5 T in the coupled QDs shows a rapid increase with increasing delay time after a linearly polarized pulse excitation, indicating the spin-injection dynamics. The $P$ value tends to decay gradually because of the exciton-spin relaxation in the QDs after the spin injection. The spin-polarized excitons in the QD ensemble migrate simultaneously from QDs with higher exciton energies to those with lower exciton energies. This inter-dot transfer of excitons also affects the $P$ value in the lower energy region of the QD-emission band because the excitons lose their spin polarizations due to the spin relaxation in the dots during the migration. The detailed analysis for the exciton-spin transfer is presented in a coupled QD system after spin injection.
|
|
| 40. |
|
|
