Share Email Print
cover

Proceedings Paper

Spin and phase relaxation dynamics in GaN and GaN/AlGaN quantum wells (Presentation Recording)
Author(s): Mathieu Gallart; Marc Ziegler; Bernd H. Hönerlage; Pierre Gilliot; Eric Feltin; Jean-François Carlin; Raphaël Butté; Nicolas Grandjean
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

By performing time-resolved optical non-degenerate pump-probe experiments, we study the relaxation dynamics of spin-polarized excitons in wurtzite epitaxial GaN and in nitride nanostructures. Those materials are indeed promising candidates for spintronic applications because of their weak spin-orbit coupling and large exciton binding energy (~ 17 meV and ~ 26meV in bulk GaN, respectively). In epilayers, we show that the high density of dislocations increases dramatically the spin relaxation of electrons and holes through the defect assisted Elliott-Yafet mechanism. That makes the exciton dephasing time very short. In high quality GaN/AlGaN quantum wells, both the exciton-spin lifetime S and the exciton dephasing-time T2 were determined via pump-probe spectroscopy using polarized laser pulses and time-resolved four wave-mixing experiments. The evolution of both quantities with temperature shows that spin relaxation occurs in the motional narrowing regime up to 80 K. Above this threshold, the thermal energy becomes large enough for excitons to escape from the QW. Such measurements demonstrate that GaN-based heterostructures can reach a very high degree of control that was previously mostly restricted to conventional III-V semiconductors and more specifically to the arsenide family.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9551, Spintronics VIII, 95510S (5 October 2015); doi: 10.1117/12.2190575
Show Author Affiliations
Mathieu Gallart, Institut de Physique et Chimie des Matériaux de Strasbourg (France)
Marc Ziegler, Institut de Physique et Chimie des Matériaux de Strasbourg (France)
Bernd H. Hönerlage, Institut de Physique et Chimie des Matériaux de Strasbourg (France)
Pierre Gilliot, Institut de Physique et Chimie des Matériaux de Strasbourg (France)
Eric Feltin, Ecole Polytechnique Fédérale de Lausanne (Switzerland)
Jean-François Carlin, Ecole Polytechnique Fédérale de Lausanne (Switzerland)
Raphaël Butté, Ecole Polytechnique Fédérale de Lausanne (Switzerland)
Nicolas Grandjean, Ecole Polytechnique Fédérale de Lausanne (Switzerland)


Published in SPIE Proceedings Vol. 9551:
Spintronics VIII
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

© SPIE. Terms of Use
Back to Top