The junction size effect on the electromigration flow of copper atoms through carbon-nanotube junctions

The size effect of carbon nanotube (CNT) channel junctions on the flow of copper atoms is investigated using molecular dynamics simulations. A bias voltage is applied along the channel to induce an electromigration force to drive the copper atoms. The study has revealed that the size of the junctions affects the configuration of copper atoms, which is reflected as a change in the potential energy. As the difference in the junction diameter increases, the surface area of the junction increases as well, leading to a higher van der Waals interaction between the junction and the copper atoms. This interaction forms a potential barrier to the copper mass, which slows down the flow of copper at the junction. The simulation results also show that the velocity of copper in the narrow section of the channel is not significantly higher than the velocity of copper in the wider section of the channel. The change in the velocity of copper at different sections of the channel is mainly due to the atomic arrangement of copper, in which the mobility of the copper mass is affected under the same electromigration condition.