Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 50: Poster II

HL 50.34: Poster

Thursday, March 30, 2006, 16:30–19:00, P3

Photoluminescence studies of GaAs quantum wells in close proximity to a GaMnAs barrier layer — •Robert Schulz, Tobias Korn, Andreas Maurer, Dieter Schuh, Werner Wegscheider, and Christian Schüller — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg

(Ga,Mn)As is a highly interesting material system for future spintronic devices, where both spin and charge of carriers are manipulated. Here, we present a study of nonmagnetic GaAs quantum wells (QW) embedded in a AlGaAs/GaAs heterostructure close to a GaMnAs barrier layer. The photoluminescence (PL) of two QWs at different distances to the GaMnAs layer is measured at low temperature. The circular polarized components of the PL are then analyzed as a function of the external magnetic field. The difference of the PL components for σ^± shows different behaviour depending on the distance between the QW and the GaMnAs layer. The PL energy of the QW closest to the GaMnAs (distance 10 nm) shows a Brillouin function type dependence, indicating a paramagnetic behaviour of the QW. For the QW farther away (100 nm) from the GaMnAs layer, a weak quadratic dependence of the PL is observed, as expected for nonmagnetic QWs. Subsequent PL measurements after several months show that the PL signal from the QW close to the barrier layer is quenched. From these observations, we suggest that there is some Mn diffusion from the barrier layer into the closest QW during and after MBE growth.