Spin relaxation times of exciton states in ZnCdSe/ZnSe low dimensional heterostructures

Citation
Y. Oka et al., Spin relaxation times of exciton states in ZnCdSe/ZnSe low dimensional heterostructures, PHYSICA E, 10(1-3), 2001, pp. 315-319
Citations number
3
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA E
ISSN journal
1386-9477 → ACNP
Volume
10
Issue
1-3
Year of publication
2001
Pages
315 - 319
Database
ISI
SICI code
1386-9477(200105)10:1-3<315:SRTOES>2.0.ZU;2-Y
Abstract
Using the pulsed excitation with a femtosecond laser and streak-camera dete ction we have studied the processes of spin relaxation in the system of loc alized excitons in low dimensional superlattices formed by the insertion of CdSe submonolayers into the ZnSe matrices. Polarization of exciton lumines cence in the magnetic field arises due to the thermal redistribution of pop ulation in the system of splitted exciton spin sublevels. The distribution of polarization across the PL band countour is governed by the complicated interplay of energy and spin relaxation processes. The study of PL decay ki netics in polarized light allows us to determine with the help of a simple two-level model the times of exciton spin relaxation. Spin relaxation times strongly decrease with the increase of magnetic field indicating the phono n assisted mechanism of spin relaxation. The detailed analysis of the depen dence of spin relaxation times on the exciton localization energy is not po ssible with the model used due to the complicated character of exciton popu lation kinetics for deeply localized states. Deeply localized states are to a great extent populated through the tunnelling relaxation of excitons wit h higher energies. The transfer of polarization in the processes of exciton energy relaxation has been clearly observed in the study of spectrally res olved decay kinetics in polarized light. (C) 2001 Elsevier Science B.V. All rights reserved.