In-situ transmission electron microscopy of structural change of the contact between a carbon nanotube and gold by local Joule heating

Contact resistance between a carbon nanotube and a metal is governed by the structure of the contact. In order to investigate an effect of the contact structure between a multi-walled carbon nanotube (MWNT) and the metal on electric properties, we studied the structural change of the contact region during the passage of a current by in-situ transmission electron microscopy with the simultaneous current and bias voltage measurements. In the case of MWNT with a closed cap, when the current density reached a threshold value (about 2.6 × 10⁸ A/cm²), the tip of the MWNT was inserted below the gold surface by local Joule heating, and the total resistance was reduced from 89 kΩ to 45 kΩ with the tip being capped. In the case of an open-ended MWNT, more significant reduction in the contact resistance was observed, but any suction phenomenon of gold into the inner cavity was not observed.