Time-resolved picosecond photocurrents in contacted carbon nanotubes.

Prechtel, Leonhard; Song, Li; Manus, Stephan; Schuh, Dieter; Wegscheider, Werner; Holleitner, Alexander W · Nano Lett · 2011

basic_science · Level V

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Abstract

We introduce coplanar stripline circuits to resolve the ultrafast photocurrent dynamics of freely suspended carbon nanotubes (CNTs) in the time domain. By applying an on-chip pump-probe laser spectroscopy, we demonstrate that CNTs, contacted by metal electrodes, exhibit a picosecond photocurrent response. We find a combination of an optically induced ultrafast displacement current, transport of photogenerated charge carriers at the Fermi velocity to the electrodes, and interband charge-carrier recombination processes to dominate the ultrafast photocurrent of the CNTs.