A Molecular Dynamics Study Of Nanowelding Of The Contact Between Carbon Nanotubes And Metal Electrodes

Carbon naotubes has a unique structure and unusual electrical properties. So it is used to build nanoelectronic devices which have small size, high speed, low power consumption and low cost, it will replace silicon as important electronic materials in the Hou Moer era. However, using carbon nanotubes to build nanoelectronic devices faces many technical problems. The connection between carbon nanotubes and metal electrodes is one of the many technical problems. People don't understand how the carbon nanotubes connect metal electrodes. The physical mechanism of connection between carbon nanotubes and metal electrodes is still in the experimental stage. In recent years, more and more people widely report how carbon nanotubes connect metal electrodes by computing simulation. It is difficult to achieve the composite structure between carbon nanotubes and metal electrodes and the structural evolution information of the cooling process by the directly experimental observation. Using first principles calculations can only be limited to a simple system, so it is best way for us to predict connection between carbon nanotubes and metal electrodes using molecular dynamics simulation.In this paper, using molecular dynamics simulation techniques, we have studied nanowelding between the gold electrodes and single-walled carbon nanotubes (SWNTs). Generally, it has many difficulties to weld for them. At about 1100K, we find that gold atoms of gold nanoclusters will enter into carbon nanotubes. More importantly, gold atoms of gold nanoclusters which are absorbed in carbon nanotubes will redistribute on the surface of the gold electrodes. Furtherly, we show that gold nanoclusters in the carbon nanotubes will form a cylindrical shape and a helical shell structure. Gold nanoclusters which are absorbed in carbon nanotubes will form a staircase shape and atomic layers structure of when annealing to room temperature. The best model is annealing at the temperature of about 800K. Include the following aspects:1. First, gold clusters are placed on open tips of SWNTs and are annealed at 1100K. Gold atoms enter into the SWNTs and form a shell-like helical structure inside the SWNTs and form an amorphous structure outside of the SWNTs.2. Furthermore, the SWNTs absorbed with gold cluster are then placed on surfaces of gold electrodes. After annealing at high temperature, gold atoms absorbed in the SWNTs redistribute on the surface of the gold electrodes and form excellent welding contact with the electrodes. The best annealing temperature for welding is about 800K.3. Last but not least, we have also studied formation processes that platinum clusters which are absorbed in SWNTs weld platinum electrodes at high temperature. After annealing at high temperature, platinum atoms form a solid structure very similar to the situation of gold atoms.