Preferential Growth of Single-Walled Carbon Nanotubes with Metallic Conductivity

TLDR

Carbon nanotube applications require either all semiconducting or all metallic tubes, yet typical synthesis yields a mixture of two‑thirds semiconducting and one‑third metallic tubes. By adjusting carrier gas, temperature, and oxidative/reductive species, the authors modify catalyst particles to selectively grow metallic single‑walled carbon nanotubes, showing that catalyst seed shape and morphology can be tuned for specific chirality. Harutyunyan et al.

Abstract

Nanotubes to Order To exploit carbon nanotubes fully in electronic applications, one needs to be able to separate or synthesize either all semiconducting or all metallic tubes. However, unbiased synthesis conditions produce a mixture containing two-thirds semiconducting tubes and one-third metallic tubes. Harutyunyan et al. (p. 116 ) show that altering the carrier gas and temperature, in combination with oxidative and reductive species during the synthesis process modifies the catalyst particles during synthesis, which leads to the selective growth of metallic single-walled carbon nanotubes. Thus, the shape and morphology of the catalyst seeds can be tuned to grow carbon nanotubes of a specific chirality.