Electric transport and mechanical strength measurements of carbon nanotubes in scanning electron microscope

We have studied electric and mechanical properties of carbon nanotubes (CNTs) using a specially designed manipulator in field emission scanning electron microscope (SEM). It is quite important to develop and realize the electrically conductive and strong bonding between CNT and electrode for new electric devices using CNT. We had bonded a CNT to some materials by the electron beam induced carbon deposition in SEM (carbon method). Furthermore, we have developed a new bonding method using a low melting point metal (alloy method) to improve the electric conductivity and mechanical strength. Then we succeeded in fabricating the alloy-CNT-alloy bridge structure with an electric resistance about 200 kOmega, which was much better than that about 500 kOmega using the carbon method. We further investigated the mechanical strength by pulling one end of the bridge and measuring the displacement of the other end of a cantilever in SEM. The mechanical strength in the case of the alloy method was estimated to be 2 GPa which was much stronger than 500 MPa in the case of the carbon method. (C) 2004 Elsevier B.V. All rights reserved.