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HL: Fachverband Halbleiterphysik
HL 36: Heterostructures
HL 36.5: Talk
Thursday, March 29, 2007, 11:00–11:15, H14
Drift Mobility of Long-living Excitons in Coupled GaAs Quantum Wells — •Andreas Gärtner1, Dieter Schuh2, Alexander Holleitner1, and Jörg Kotthaus1 — 1Department für Physik and Center for NanoScience, Ludwig-Maximilians-Universität, D-80539 München, Germany — 2Institut für Angewandte und Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany
Photo-generated electron-hole pairs in quantum well devices can be manipulated in lifetime and position via a mesoscopic voltage-controlled electrostatic landscape [1]. Here we employ the quantum confined Stark effect in a coupled double quantum well to generate spatially indirect excitons with lifetimes exceeding 1 µs and to study their motion induced by a controlled spatial variation of the out-of-plane electric field [2,3]. Macroscopic drift of excitons is studied in a time-of-flight experiment employing a laterally graded electrostatic potential induced via a current-carrying resistive gate [2]. This allows us to determine the drift mobility of such long-living excitons. Across several hundreds of microns a drift mobility exceeding 105 cm2/eVs is observed for temperatures below 10 K. With increasing temperature the excitonic mobility decreases due to exciton-phonon scattering.
[1] for a recent review, see e.g.: J. P. Kotthaus, Phys. Stat. Sol. b 243, 3754 (2006). [2] A. Gärtner, A. W. Holleitner, J. P. Kotthaus, D. Schuh, Appl. Phys. Lett. 89, 052108 (2006). [3] A. Gärtner, D. Schuh, J. P. Kotthaus, Physica E 32, 195 (2006).