Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Group IV (other than C): Si/Ge/SiC
HL 25.9: Vortrag
Mittwoch, 3. April 2019, 11:45–12:00, H33
Time-resolved spectroscopic ellipsometry on Ge and Si — •Steffen Richter1, Shirly Espinoza1, Oliver Herrfurth2, Mateusz Rebarz1, Rüdiger Schmidt-Grund2, Jakob Andreasson1,3, and Stefan Zollner4 — 1ELI Beamlines, Za Radnicí 835, Dolní Břežany, Czech Republic — 2Universität Leipzig, Felix-Bloch-Instiut für Festkörperphysik, Linnéstr. 5, 04103 Leipzig, Germany — 3Chalmers tekniska högskola, Institutionen för fysik, Kemigården 1, 41296 Göteborg, Sweden — 4New Mexico State University, Department of Physics, PO Box 30001, Las Cruces, NM, 88003-8001, USA
Highly excited semiconductors feature a large number of concurrent processes of carrier scattering, relaxation, ambipolar diffusion and recombination. Discriminating them and understanding their dynamics is crucial for potential applications. To this aim, the distinction between amplitude and phase information of the optical response is essential. This cannot be provided by conventional transient spectroscopy. Here, we report on recent progress in developing pump-probe broadband ellipsometry with sub-picosecond resolution. We present measurements carried out on Ge, Si and InP single crystals. The obtained pseudo dielectric-functions hint on band gap renormalization of higher conduction bands and band filling by electrons at the minima of the conduction band. Their dynamics allow to understand scattering mechanisms for the hot charge carriers, and also indicate phonon coupling.