Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 6: Ge/Si I
HL 6.3: Vortrag
Montag, 26. März 2012, 10:00–10:15, EW 203
Ultra-fast intersubband-relaxation and the evidence of non-thermal carrier distribution in Ge/SiGe quantum wells — •Alexej Chernikov1, Verena Bornwasser1, Martin Koch1, Niko Köster1, Ronja Woscholski1, Sangam Chatterjee1, Eleonora Gatti2, Emanuele Grilli2, Mario Guzzi2, Danny Chrastina3, and Giovanni Isella3 — 1Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg, Renthof 5, D-35032 Marburg, Germany — 2L-NESS and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 53, I - 20125 Milano, Italy — 3L-NESS and Dipartimento di Fisica, Politecnico di Milano, Polo Territoriale di Como, via Anzani 42, I - 22100 Como, Italy
In the last decade, optical properties of Ge/SiGe-heterostructures have received much attention in the scientific community being a possible candidate for the realization of a semiconductor laser on Si-substrates. In addition, the optical properties of the material system are of fundamental interest due to the combination of a direct transition only slightly higher in energy than the indirect band-gap. Further advantages are the enhancement of the light-matter coupling as well as the tunability of the band strucure, both inherent for the low-dimensional systems. Here, we present a systematic study of carrier relaxation in Ge/SiGe quantum wells applying photoluminescence and pump-probe spectroscopy. Ultra-fast intersubband-relaxation on a 100 fs time-scale and the presence of a non-thermal carrier distribution are found to strongly influence the optical response of the material.