Computer analysis of buckminsterfullerene on a silicon (111)-7 x 7 surface.

Abstract

This work uses STM-scanning tunneling microscope and computers to study the interaction of two different materials. The equipment used are STM-scanning tunneling microscopy and computers. The materials are the silicon (111)-7 x 7 surface and the carbon 60. The C₆₀ topic has been widely discussed since 1990. The basic properties of C₆₀ molecules have been reviewed in this work. The silicon surface is important for the current electronic industry, but the silicon surface structure was not well known until 1985. STM is the best technique to image C₆₀ on the silicon surface in the real space domain. In chapter one and chapter two, I discuss the background of this topic and the principles of my experiment. The interaction of C₆₀ with the Si (111)-7 x 7 surface has been seen clearly on STM images, but the nature of the interaction is not well known. The primary question is where these C₆₀ molecules prefer to stay on the Si (111)-7 x 7 surface? I made a computer to answer this question by using a sophisticated program package to do image recognition. To explain the interesting statistical result, a very simple physical model has been constructed and calculations by the theoretical model are fitted to the experiment result. Molecular dynamical computer simulation is one of the most powerful tools for studying assemblies of particles interacting through realistic inter-particle forces. I used this method to calculate the C₆₀ and silicon (111)-7 x 7 in van der Waals force interaction to see if the result can fit the experiment or not. The conclusion is that the interaction between C₆₀ and Si (111)-7 x 7 is not dominated by van der Waals forces. Image processing techniques are very important in this work. I devoted one chapter to describe the image processing in my data analysis. The technique I used here is not only good for the current work, it also could be used in other research areas. Chapter six discusses a simulation calculation to study scanning force microscope tip and sample interaction. The whole chapter is a paper that has been published in Nanotechnology.