Photogenerated free carrier dynamics in metal and semiconductor single-walled carbon nanotube films.

Beard, Matthew C; Blackburn, Jeffrey L; Heben, Michael J · Nano Lett · 2008

basic_science · Level V

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Abstract

Time-resolved THz spectroscopy (TRTS) is employed to study the photogenerated charge-carrier dynamics in transparent films of single-walled carbon nanotubes (SWNTs). Two films were investigated: a film with 94% semiconducting-type tubes (s-SWNTs) and a film with only 7% s-SWNT and 93% metal-type tubes (m-SWNTs). We conclude that charge-carriers are generated with >60% yields at low light intensities in both films. Free-carriers are generated by a linear exciton dissociation process that occurs within -1 ps and is independent of excitation wavelength or tube type.