Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 66: Transport Properties III (Experiments)
HL 66.1: Talk
Wednesday, March 28, 2012, 18:15–18:30, ER 164
Picosecond time-resolved photocurrents in GaAs nanowires — •Nadine Erhard1, Leonhard Prechtel1, Milan Padilla1, Helmut Karl2, Gerhard Abstreiter1, Anna Fontcuberta3, and Alexander Holleitner1 — 1Walter Schottky Institut and Physik-Department, TU München, Am Coulombwall 4a, D-85748 Garching, Germany — 2Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany — 3Laboratoire des Materiaux Semiconducteurs, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne, Switzerland
Conventional scanning photocurrent microscopy (SPCM) experiments on semiconductor nanowires are typically limited to timescales exceeding 10 ps. Yet, it is known from optical experiments that carrier relaxation and transport processes can occur on much faster timescales in semiconducting nanowires. We therefore apply a recently developed pump-probe photocurrent spectroscopy to investigate the photocurrent dynamics of p-doped GaAs nanowires with a picosecond time-resolution. Hereby, the ultrafast photocurrent response of the nanowire is sampled at a field probe in a stripline circuit. We discuss ultrafast thermoelectric, displacement, and carrier lifetime limited currents as well as the time-resolved transport of photogenerated holes.