Based On The AFM Carbon Nanotube Tip Molecular Dynamics Simulation

Atomic force microscope (AFM) plays a key role in the development of nanotechnology and provides a powerful method for studying the materials topography and micro-interaction between samples. However, the shape and physical characteristics of ordinary AFM probe limit its application. An ideal AFM tip must have high aspect ratio, small curvature radius, identified molecular structure and stable physical and chemical characteristics. Carbon nanotube (CNT) is considered as ideal AFM probe for its multiple excellent characteristics. In order to combine the advantages of the precision instrument of AFM and the"super fiber"of carbon nanotube, there had been a lot of successful experiments in the production of carbon nanotube atomic force microscope probe. But the assembling dynamics is very difficult for the experiment on carbon nanotube and diamond tip of the bonding process for tracking dynamic observation. Many of the details of the atom could not be solved, made"based on the atomic force microscope tip of carbon nanotube molecular dynamics simulation"this leading edge research topics.In this thesis, molecular dynamics simulation based on the Brenner potential were performed to study the interaction of atoms. At first, the basic concept and theory about molecular dynamics are introduced. The choosing potential of atoms, algorithm of motion equations and boundary condition and initial condition are especially studied. On these foundations, models of the CNT welding on diamond tip simulation experiment are established and Brenner potential is detailed deduced which is used to describe the interactions of C atoms. The related simulation programs are established.We researched SWNTs molecule assembling on diamond tip (100) crystal surface with impacting energy, carbon nanotubes chiral, length, diameter and other factors, found that the length of carbon nanotubes need more than 3nm in diameter greater than 0.8nm. Carbon nanotubes can be a one-dimensional linear cylindrical structure with the length of carbon nanotubes more than 3nm and diameter greater than 0.8nm. In a zigzag (10×0) single-walled carbon nanotube as a samples, carbon nanotube and diamond tip bonding energy window is 12~ 90eV. Studied of single-walled carbon nanotube and diamond tip of the position eccentric, we get the best of the initial state bonding, tilt angle of 0°to 20°, the incident energy 30~60eV. Eccentricity is almost unaffected with less than one-third of the radius of carbon nanotube or greater than the radius.