Chirality assignment of individual single-walled carbon nanotubes in carbon nanotube field-effect transistors by micro-photocurrent spectroscopy

We have proposed a possibility of chirality assignment of individual single-walled carbon nanotubes in nanotube field-effect transistors (FETs) by micro-photocurrent spectroscopy. The nanotube FETs were fabricated by utilizing position-controlled nanotube growth technique using alcohol chemical vapor deposition. Photocurrent signal that originated from a single single-walled carbon nanotube was obtained by using microscopic optical measurement system. A peak was observed at 1.73 eV in the photocurrent excitation spectrum. This corresponds to optical absorption by van Hove singularity of the nanotube with a diameter of similar to2 nm. Chirality of the nanotube in the nanotube FET was assigned to be (18, 10) by comparing the experimental results with theoretical calculation. (C) 2004 American Institute of Physics.