si111表面化学修饰graphene吸附行为及新型二维sic2材料预测-adsorption behavior of graphene chemically modified on si 111 surface and prediction of new two-dimensional sic 2 material.docx

关键词：Si(111)表面，SiC2，纳米晶片，表面重构，石墨烯，修饰，物理吸附，电子性质，密度泛函理论AbstractGraphene, a single layer of carbon atoms arranged in a honeycomb lattice, is a typical sp2-hybrid material. It is considered as a potential candidate to replace Si as the basic material for next generation nanoelectronic device due to its excellent electronic properties. The realization of the synthesis of graphene on Si surface is the foundation of graphene in combination with Si technology. To preseve the electronic character of graphene on the Si(111) surface is the premise for graphene-based nanodevices. In this paper, we investigate the electronic characteristics of graphene on the C-decorated Si(111) surface which provides some theoretical fundamentals for the growth of graphene on the Si surface. In our present work we also find a new kind of SiC2 two-demisonal material, its structure and electronic properties are predicted . The main points of our present work are as follows:First principles calculations based on the density functional theory are performed to study electronic structures of graphene adsorbed on clean or C-decoratedSi(111) surface. Two types of surface reconstructions,2 ??2and3 ????3 , areconsidered to be decorated by carbon atoms with different concentrations. Firstly, wefind that graphene adsorbed on ideal clean Si(111) surface tends to induce a2 ?1reconstruction, and the electronic characteristics of graphene are preserved. We find that the decoration of carbon atoms on the Si(111) surface can effectively passivate the Si dangling bonds on the surface. Such decoration effects make the carbon decorated Si(111) surfaces promising substrate for graphene which preserves the excellent electronic structure of graphene;We investigate the the modified effect of hydrogen(H), boron(B), nitrogen(N), fluorine(F) adsorbed Si(111) surface on the electronic properties of graphene by using the fisrt-principles method based on density functional theory. The results indicate