Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 16: Poster Ia

HL 16.4: Poster

Freitag, 4. März 2005, 16:30–19:00, Poster TU E

Optical spin injection from (Zn,Mn)Se into GaAs/(Al,Ga)As quantum wells — •Wolfgang Löffler, Daniel Tröndle, Thorsten Passow, Bruno Daniel, Miriam Kantner, Michael Hetterich, Michael Grün, Claus Klingshirn, and Heinz Kalt — Universität Karlsruhe (TH), Center for Functional Nanostructures (CFN) and Institut für Angewandte Physik, Wolfgang-Gaede-Str. 1, D-76128 Karlsuhe

The efficient injection of spin polarized charge carriers into semiconductor nanostructures is currently a field of intense research.

Using a confocal magneto-P technique we optically excite spin-polarized excitons in a semimagnetic (Zn,Mn)Se layer and detect the photoluminescence signal and its polarization state from a GaAs/(Al,Ga)As quantum well. The MBE-grown samples are placed in a magnetic cryostat at fields up to 14T and temperature T=4K. Comparing the measured circular polarization degrees of the photoluminescence signal in dependence of the excitation polarization we calculate the magneto-polarization, i.e. the degree of circular polarization induced by the magnetic field, which reaches values of up to 0.2. The actual injection efficiency is much higher but is to some extent masked by the fact that only 20% of the exciting light is absorbed within the (Zn,Mn)Se layer.

Currently we extend our work to electrical spin injection from doped (Zn,Mn)Se DMS layers into (In,Ga)As quantum wells.