Regensburg 2016 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 23: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy
O 23.7: Poster
Montag, 7. März 2016, 18:15–20:30, Poster E
Ultrafast thermionic injection currents in metal-insulator-metal junctions — •Felix Becker1, Detlef Diesing2, Dominik Differt1, Matthias Hensen1, Walter Pfeiffer1, and Christian Strüber3 — 1Molekül- und Oberflächenphysik, Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld, Germany — 2Surface Dynamics Group, Fakultät für Chemie, Universität Duisburg-Essen, 45141 Essen, Germany — 3Quantum Optics and Laser Science Research Group, Imperial College London, SW7 2AZ London, GB
Recently, it has been shown that plasmonic resonances at structural defects on the top electrode of the heterosystem facilitate the injection of charge carriers above the tunnel barrier of the oxide [1]. Here, we exploit the enhanced excitation in the vicinity of gold nanoparticle antennas deposited on the top electrode of a metal-insulator-metal junction to inject charge carriers in the counter electrode. Instead of multi-photon processes or strong field effects, we identify highly localized thermionic emission as the dominating process for current injection. Here the theoretical model describing the experimental observations is presented. It is based on the calculated electromagnetic field distribution, simulated excited electron relaxation cascades and solutions of the three-dimensional heat diffusion equation. The large temperature gradients in the electron gas and the corresponding ultrafast temperature transients give rise to highly localized and ultrafast thermionic injection currents. An injection current pulse duration of about 20 fs is obtained although the thermionic emission is dominating.
[1] D. Differt et al., Appl. Phys. Lett. 101, 111608 (2012)