Sorting single-walled carbon nanotubes by strain-based electrical burn-off

Armchair metallic single-walled carbon nanotubes (SWCNTs) retain their high symmetry under tensile stretching, and their electrical properties are the least sensitive to tensile strain. Other types of SWCNTs with lower symmetries, including quasi-metallic (or small band-gap semiconducting) and semiconducting SWCNTs, are more sensitive and can exhibit band-gap changes under tensile stretching. In this study, we demonstrate a simple and reliable method for selectively removing armchair metallic SWCNTs from suspended SWCNT arrays to tailor the strain property of these composite SWCNTs. Our method takes advantage of the band-gap changes of three SWCNT species with respect to strain. Proof of the effectiveness of selection is given by a comparative strain sensitivity study on the initial and treated SWCNT arrays.