Engineering Carbon Nanotubes and Nanotube Circuits Using Electrical Breakdown

TLDR

Carbon nanotubes can be metallic or semiconducting, and both multiwalled nanotubes and aligned single‑walled nanotube ropes are complex composite conductors composed of many weakly coupled nanotubes with distinct electronic structures. The study demonstrates a simple, reliable method to selectively remove single carbon shells from MWNTs and SWNT ropes to tailor their properties. The method removes MWNT shells stepwise and allows individual characterization of each shell. Selective shell removal converts MWNTs into either metallic or semiconducting conductors and resolves multi‑shell transport, while in SWNT ropes it enables arrays of nanoscale field‑effect transistors based solely on the semiconducting fraction.

Abstract

Carbon nanotubes display either metallic or semiconducting properties. Both large, multiwalled nanotubes (MWNTs), with many concentric carbon shells, and bundles or “ropes” of aligned single-walled nanotubes (SWNTs), are complex composite conductors that incorporate many weakly coupled nanotubes that each have a different electronic structure. Here we demonstrate a simple and reliable method for selectively removing single carbon shells from MWNTs and SWNT ropes to tailor the properties of these composite nanotubes. We can remove shells of MWNTs stepwise and individually characterize the different shells. By choosing among the shells, we can convert a MWNT into either a metallic or a semiconducting conductor, as well as directly address the issue of multiple-shell transport. With SWNT ropes, similar selectivity allows us to generate entire arrays of nanoscale field-effect transistors based solely on the fraction of semiconducting SWNTs.