Local Change of Carbon Nanotube-Metal Contacts by Current Flow through Electrodes

Abstract

The new processes of current flow through electrodes at carbon nanotube (CNT)-electrode junctions were carried out to change the contact resistance of CNT conductors and the tunnel barriers of CNT quantum dots. When the current flow process was applied to CNT conductors with the Au/Ti electrodes deposited on multiwall CNTs (MWNTs), the contact resistance markedly decreased. This is caused by the formation of titanium carbide (TiC) at the electrode-nanotube junction due to the strong interaction between Ti and nanotubes. This process is useful for obtaining the CNT conductor with low contact resistance. Meanwhile, when the current flow process was applied to single-wall CNT (SWNT) quantum dots with Au-Ag alloy electrodes, the contact resistance hardly changed due to the weak nanotube-Au-Ag interaction. However, in the electrical measurement of these samples at low temperatures, a quantum dot with a strong confinement was obtained after the current flow process. Therefore, this process can be also used for the change of tunnel junctions of CNT quantum dots.