Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 21: III-V semiconductors II

HL 21.2: Talk

Tuesday, March 27, 2007, 11:15–11:30, H17

Exciton transport by surface acoustic waves — •Jörg Rudolph, Rudolf Hey, and Paulo Santos — Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin

We present a novel approach for the transport of excitons in GaAs quantum wells (QW) using the mobile strain field of a surface acoustic wave (SAW). The strain field of a SAW travelling along the [100] direction on a (001)GaAs structure leads to a moving lateral type-I band gap modulation. Long-living indirect excitons photoexcited in a double-quantum well structure are trapped close to the positions of minimum band gap and transported with the acoustic velocity. The transport is detected by spatially resolved photoluminescence (PL) to image excitonic recombination away from the excitation spot. We investigate the dependence of the transport on the applied acoustic power and extract information about the exciton mobility. Mechanisms for exciton confinement in the SAW-induced potential are discussed.