Study Of Organic Compounds On Si (100) Surface Reaction Mechanism

Modern silicon-based microchip processing uses top-down pattern,changing the size of the device into smaller and smaller.According to Moore's Law,when the device size is less than the critical size,the conventional semiconductor process will no longer apply.Therefore,the use of elements of the electrical properties of the preparation for molecular electronic devices has become more and more popular.At the time when experiments flourished,theoretical workers developed a variety of theoretical models and methods,which successfully explained the results of the experiments,and even designed a number of models of molecular devices theoretically.This thesis mainly studies the reaction mechanism of the organic small molecule compounds on the surface of Si(100) through density functional theory and electron transport theory respectively.These researches will provide certain theoretical basis for the reaction mechanism of small organic molecules on the surface of Si(100).This thesis mainly consists of four chapters.In the first chapter we briefly review the development history of molecular electronics research and current situation.After a brief comment of the recent developments of the study of molecular electronics,the thesis focuses on several frequently used conceptions,such as molecular switches,molecular rectifier,ene reactions,etc.Later,we introduce a number of molecular systems and their electronic transport properties that have been studied a lot,such as rectification,negative differential conductance and the switch effect,as well as the reaction mechanism of some small organic molecules on the surface of Si(100).ChapterⅡpresents the theoretical calculation method used in this thesis.In the first part of this chapter,we first briefly reviewed the development of quantum chemistry,and in the latter part introduced electronic density functional theory,ab initio calculation principle, pseudopotential ab initio valence orbital.In ChapterⅢ,we apply Gaussian package with DFT methods to study carbonyl compounds adsorption reaction on Si(100) surface.Through the study,we found that the reaction of the carbonyl compounds on the Si(100) surface has two reaction paths,namely,[2+2] cycloaddition reaction and the ene reaction.Ene reaction path is more easily than[2 +2] cycloaddition reaction.The reaction is controlled by thermodynamic.In ChapterⅣ,we apply Gaussian package with DFT methods to study the adsorption reaction on the surface of Si(100).The results show that there are two reaction paths when the adsorption reactions take place on the surface of Si(100):one is first to generate Si-O dangling bonds of the intermediates,and then to generate the product of ene aider a transition state;the second path is first to generate Si-N dangling bonds of the intermediates,and then to generate the product of ene after a transition state.Compared with the second path,the former one is much more easily to be conducted.