Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 20: Spin controlled transport II

HL 20.1: Vortrag

Dienstag, 28. März 2006, 15:15–15:30, BEY 118

Vertical cavity surface emitting lasers for amplification of spin information at room temperature — •Stephan Hövel¹, Nils C. Gerhardt¹, Martin Hofmann¹, Junling Yang², Dirk Reuter², and Andreas D. Wieck² — ¹AG Optoelektronische Bauelemente und Werkstoffe, Ruhr-Universität Bochum, IC2/152, 44780 Bochum — ²Angewandte Festkörperphysik, Ruhr-Universität Bochum, NB 03, 44780 Bochum

Spin injection into semiconductor light emitting diodes at room temperature usually results in effects much too small for applications. This is due to low injection efficiencies and, in particular, to strong spin relaxation in the semiconductor. We show experimentally and theoretically that spin information can be amplified using the nonlinearity of vertical cavity surface emitting lasers at threshold. By polarized optical excitation of a GaInAs VCSEL we can achieve an output polarization which is higher than that of the excitation [1]. For further improvement, we analyse the spin relaxation in different semiconductor materials to determine the optimal active material for a spin-VCSEL. Finally, we discuss electrical injection schemes for room temperature and low external magnetic fields [2].We thank the DFG for providing support in the SFB 491.

[1] S. Hövel, N. Gerhardt, M. Hofmann, J. Yang, D. Reuter and A. Wieck, Electronics Letters 41, 251 (2005)

[2] N. C. Gerhardt, S. Hövel, C. Brenner, M. R. Hofmann, F.-Y. Lo, D. Reuter, A. D. Wieck, E. Schuster W. Keune and K. Westerholt, Appl. Phys. Lett. 87, 032502 (2005)