Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 42: Focussed Session: Silicon Photonics
HL 42.4: Topical Talk
Mittwoch, 24. März 2010, 15:30–16:00, H13
Transient optical gain in Germanium quantum wells — •Christoph Lange1,2, Niko Köster1, Martin Schäfer1, Mackillo Kira1, Stephan Koch1, Danny Chrastina4, Giovanni Isella4, Hans von Känel4, Hans Sigg3, and Sangam Chatterjee1 — 1Faculty of Physics and Material Sciences Center, Philipps-Universität, Renthof 5, D-35032 Marburg, Germany — 2Department of Physics University of Toronto 60 St. George St. Toronto ON, M5S 1A7 Canada — 3Laboratory for Micro and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland — 4CNISM and L-NESS, Dipartimento di Fisica del Politecnico di Milano, Polo di Como, via Anzani 42, I-22100 Como, Italy
One of today’s most-sought goals in semiconductor technology is the monolithic integration of microelectronics and photonics on Si.
Optical gain is, in general, not expected for Si and Ge or its alloys due to the indirect nature of the band gap in this material system.
Here, we show that Ge/SiGe QWs show transient optical gain and may thus be used as an optically-pumped amplifier at room temperature [1].
Further, the nonequilibrium effects which govern the relaxation dynamics of the optically injected carrier distributions in this material were observed
and analyzed using a microscopic many-body theory.
Strong non-equilibrium gain was obtained on a sub-100 fs time scale.
Longlived gain arising from Γ-point transitions is overcompensated by a process bearing the character of free carrier absorption.
C. Lange et al., Phys. Rev. B 79, 201306(R) (2009)