Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 48: Focus Session: Spintronics (jointly with MA)
HL 48.10: Talk
Wednesday, March 28, 2012, 12:30–12:45, EW 201
Spin relaxation dynamics in spin-LEDs — •Henning Höpfner1, Carola Fritsche1, Arne Ludwig2, Astrid Ebbing2, Frank Stromberg3, Heiko Wende3, Werner Keune3, Dirk Reuter2, Andreas D. Wieck2, Nils C. Gerhardt1, and Martin R. Hofmann1 — 1Photonics and Terahertz Technology, Ruhr-University Bochum, Germany — 2Applied Solid State Physics, Ruhr-University Bochum, Germany — 3Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Germany
In recent years, spin-optoelectronics has been a field of both extensive and intensive research. In particular, the fabrication of spin light-emitting diodes (LEDs) has been intensively investigated.
Here we present a detailed investigation of spin injection into spin quantum dot LEDs. Our samples are GaAs based pin-type diodes and consist of a MgO tunnel barrier capped with a Fe/Tb multilayer injector operating in magnetic remanence and InAs quantum dots in the active region. The Fe/Tb multilayer allows us to operate our devices in magnetic remanence, which enables the separation of spin injection and relaxation effects from parasitic effects due to external magnetic fields (Appl. Phys. Lett. 99 (5), 051102 (2011)).
In this study we focus on spin relaxation during transport to the active region and spin relaxation in the active region prior to carrier recombination. Using a series of samples with varying injection path length we analyze relaxation during transport, while the ratio of carrier lifetime to spin lifetime determines the degree of polarization of the emission from the device.