Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 17: Poster Ib
HL 17.11: Poster
Freitag, 4. März 2005, 16:30–19:00, Poster TU F
Transport of spin-polarized excitons in Zn1−xMnxSe-based II-VI heterostructures — •B. Daniel, W. Löffler, D. Tröndle, C. Klingshirn, H. Kalt, and M. Hetterich — Institut für Angewandte Physik and Center for Functional Nanostructures (CFN), Universität Karlsruhe, D-76131 Karlsruhe, Germany
In order to study the transport of spin-polarized excitons through II-VI heterostructures in a magnetic field, polarization-resolved photoluminescence (PL) was measured on a series of different semiconductor heterostructures grown on GaAs by molecular beam epitaxy. To align the exciton spin, either ZnMnSe layers or short-period superlattices (ZnSe/MnSe or CdSe/ZnMnSe) were used. By measuring the PL shift of the latter as a function of the applied magnetic field, the effective g factor could be determined for the different structures. The circular emission detected proved that exciton spin polarization indeed took place. The heterostructures investigated consisted of a buffer layer (ZnSe), a quantum well (CdSe or ZnCdSe), a barrier (ZnSe) and a spin aligner layer (one of the above). In order to clarify the role of different contributions to the polarization degree of the quantum well PL polarization, a series of such structures was grown and investigated, varying in the Mn or Cd content of the spin aligner layer, the thickness of the barrier, and the Zn content in the quantum well. Additional information was deduced from experiments with different excitation wavelength.