In situ measurements on individual thin carbon nanotubes using nanomanipulators inside a scanning electron microscope

We demonstrate here a novel method for performing in situ mechanical, electrical and electromechanical measurements on individual thin carbon nanotubes (CNTs) by using nanomanipulators inside a scanning electron microscope. The method includes three key steps: picking up an individual thin CNT from a substrate, connecting the CNT to a second probe or an atomic force microscope cantilever for the measurements and placing the CNT onto a holey carbon film on a transmission electron microscope grid for further structure characterization. With the method, Young's modulus, the breaking strength and the effects of axial strain on electrical transport properties of individual thin CNTs can be studied. As examples, the mechanical, electrical and electromechanical properties of a double-walled CNT (DWCNT) and a single-walled CNT (SWCNT) were measured. We observed a strain-induced metallic-to-semiconducting transition of the DWCNT and a bandgap increase of the SWCNT. More importantly, the electromechanical properties of the SWCNT were correlated to its chirality determined by electron diffraction. The method enables us to relate mechanical, electrical and electromechanical properties of the measured thin CNTs to their atomic structures.