Contact resistance between individual single walled carbon nanotubes and metal electrodes

We report that ohmic contact between individual single walled carbon nanotubes (SWNTs) and palladium (Pd) was formed by using the electric-current-induced joule beating in Pd electrode. The SWNTs are deposited onto Pd electrode patterned on SiO2/Si substrate, through which the electrical currents flow for microseconds. As a result, transport measurement exhibited a decrease in contact resistance between individual SWNT and Pd electrode from 3.3 MOmega to 176 kOmega at room temperature after joule beating induced by the electrical current. Atomic force microscopy also showed that a surface of Pd metal is smoothened in roughness after electrical current flowing, indicating metallic melting by joule heat. Therefore, we suggest the way to achieve a low contact resistance between SWNT and metal in field effect transistor at room temperature, instead of thermal annealing method at high temperature.