Molecular Dynamics Simulation Of Joining Process Between Carbon Nanotubes And Metal Nanoparticles

The dimension of microelectronic circuits based on traditional materials is hardto decrease due to the limit of technology. Thus molecular electronic circuits arise atthe historic moment. Carbon nanotube (CNT), with its unique nanostructure andelectronic properties, has become one of the most competitive candidate in futuremicroelectronic manufactures. However, in this transition time, the issue ofcompatibility between CNT and traditional circuits stands in the way, specifically thereliable joining between CNT and metal electrodes. Up to now, many techniqueshave emerged to fulfill joining between CNT and metal electrodes, yet still with a lotof problems left, such as observation and measuring difficulties. Studies onnanojoining mostly focus on manipulating methods whereas applications depend asmuch on the microstructure and performance of the joint. Thus it’s necessary toperform proper analysis on this issue.In this paper, molecular dynamics is firstly applied to model the joining processof CNT and Co, Ni and Au nanoparticles based on a novel bond-order many-bodypotential function for carbon-metal force field. It shows that the main joining processis made up of the diffusion of metal atoms to CNT. Joint structure is formedcombining the flexibility of CNT and the lattice structure of metal atoms. Enddeformation of the CNT and disordering of metal atoms are both found. Metal suchas Co who bonds too strongly with CNT diffuses severely inside it, causing collapseof CNT, which is unfavorable in practice.By using Au as a representative electrode, changing original geometricalstructures of two materials and thermodynamic environment conditions, the mainfactors which determine the joining process and joint structure are studied. It isshown that the hexatomic rings arrangement, the CNT diameters, shell numbers,surface conditions, temperature and pressure all influence the joining process andjoint structure to some extent. Particle size affects the joining due to the difference ofatoms number and specific surface energy, while the direction of the lattice planeshows little influence on the joint structure. All above influences appear in thediffusion status of Au atoms and C-Au bonds number.Moreover, taking into consideration the impacting and vibration environmentduring the transportation and utility, as well as the requirement of heat dissipation inmicroelectronic circuits, both mechanical and thermal properties of the joints arestudied, which is a theoretical guidance for future manufacturing of CNT basedmicroelectronic circuits. The degree of disorder determines the joint property, where a higher degree of disorder leads to a better joint with larger displacement bearingability and lower thermal resistance.