Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 50: Graphene and Carbon Nanotubes

HL 50.9: Vortrag

Donnerstag, 25. März 2010, 11:45–12:00, H15

Time-resolved ultrafast photocurrent spectroscopy using THz stripline circuits on carbon nanotubes — •Leonhard Prechtel¹, Li Song², Stefan Manus², Dieter Schuh³, Werner Wegscheider^3,4, and Alexander Holleitner^1,2 — ¹Walter Schottky Institut and Physik Department, TUM Garching, Germany — ²Fakultät für Physik and Center for NanoScience (CeNS), LMU München, Germany — ³Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany — ⁴Laboratorium für Festkörperphysik, HPF E 7, ETH Zürich, Switzerland

The exciton dynamics in carbon nanotube devices are typically detected in a time-resolved way by optical techniques such as the transient absorption technique and the time-resolved photoluminescence spectroscopy. Both methods focus mainly on the dynamics of charge carriers within carbon nanotubes. Many questions remain concerning the separation and the transport of photo-generated charge carriers to source and drain leads. We address these questions by a novel ultrafast photocurrent spectroscopy, which is based on a common pump-probe technique. The experimental setup with a picosecond time-resolution will be introduced, and first results of the time-resolved photocurrent of carbon nanotubes will be shown. We will discuss polarization and charge separation effects within the carbon nanotubes as well as the influence of hot phonons, the bath temperature, and the bias voltage on the photocurrent across carbon nanotubes.