Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.35: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

Comparison of different techniques to determine long spin lifetimes in slightly n-doped GaAs bulk and GaAs/AlGaAs quantum wells — •Michael Griesbeck, Andreas Maurer, Sebastian Fehringer, Robert Schulz, Tobias Korn, Dieter Schuh, Werner Wegscheider, and Christian Schüller — Universität Regensburg, Germany

A key issue of spintronics research is the search for materials with long spin lifetime. The commonly used technique for the determination of spin lifetimes, ultrafast time-resolved Faraday/Kerr rotation (TRFR/TRKR), is limited to a short time window of a few ns by some reasons like the pulse repetition rate of the used pulsed laser or the length of the available delay line.Here we present a study about the comparison of the well-known TRFR technique with two other optical techniques, the so-called resonant spin amplification technique (RSA) on the one hand and Hanle-MOKE measurements on the other hand. The measurements are done on samples of slightly n-doped GaAs bulk and Mn-doped GaAs/AlGaAs quantum wells, where long spin lifetimes were detected earlier. We compare the results for spin lifetime from the different techniques in 3D and 2D systems. Spin lifetimes were extracted for different excitation and probing intensities for different Laser spot sizes, partially using a microscope setup, focussing the spot down to a few microns. The observed spin lifetimes range from about 1 ns to 120 ns and could be measured with an accuracy of a few percent.