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O: Fachverband Oberflächenphysik
O 8: Ultrafast Electron Dynamics I: Surfaces and Interfaces (joint session O/MA)
O 8.9: Vortrag
Montag, 16. März 2020, 12:30–12:45, TRE Phy
Time-resolved nonlinear optical spectroscopy of ultrafast charge transfer at the buried GaP/Si(001) interface — •Gerson Mette1, Jonas Zimmermann1, Alexander Lerch1, Kristina Brixius1, Jens Güdde1, Andreas Beyer1, Michael Dürr2, Kerstin Volz1, Wolfgang Stolz1, and Ulrich Höfer1 — 1Fachbereich Physik, Philipps Universität Marburg, Germany — 2Institut für Angewandte Physik, Justus-Liebig-Universität Giessen, Germany
The ongoing miniaturization increases the contribution of interface processes to electronic device properties. For a microscopic understanding, the dynamics of charge transfer across interfaces are particularly important. However, due to the experimental difficulty to detect and isolate the weak interface signature from the dominant bulk signals, direct experimental information about the ultrafast dynamics at buried interfaces is scarce.
Here, we will show that the experimental challenges can be overcome by optical second-harmonic generation (SHG), a technique which is intrinsically highly interface sensitive. We are investigating the ultrafast charge-carrier dynamics at the buried interface of GaP on Si(001) by time-resolved optical-pump SHG-probe spectroscopy. Photon energy dependent measurements reveal the existence of electronic interface states in the band gap of both materials. Charge carriers excited via these interface states are efficiently injected within a few hundred femtoseconds from the GaP/Si interface into the Si substrate resulting in the build-up of an electric field on a picosecond time scale.