The Structure Deformation And Elelctronic Properties Of The Graphene

Graphene, which was discovered by Novoselov in 2004, it has attracted a lot of attentions all around the world by its special structure and properties. The graphene has an excellent lattice structure,small dimension,quantum effect properties, these make graphene has the excellent properties, such as high electron mobility,high strength,good thermal property and so on. It is possible that the graphene will become the substitute of the silicon material to produce super computer in the future, and it also can be made into the space lift, it is a new material which can be applied in many areas. The research of graphene has the important significance to our technology and lives in future.In this paper, we choose the different graophene sheets to study their electronic properties, including geometric,Energy levels,Molecular Orbits,Spectra analysis and electronic transmission characteristics. The thesis is divided into six chapters.In chapter I, review the physical properties and the current research of graphene, and makes an introduction of preparation of graphene.In chapter II, introduce the theoretical basis for this paper, including abinitio, semiempirical molecular orbital method,the density function theory, Green function and so on.In chapter III, The orbital energies and the frequencies of the six benzene rings graphene graphene have been studied by using B3LYP method and 6-31G(d)basic set. The molecular energy levels,orbital density and the vibration spectrum are obtained and discussed.In chapter IV, The electronic properties of the round graphene have been studied by using B3LYP method and 6-31G(d)basic set. The geometric structure,Frontier orbits,Milliken Charge and vibration spectrums are obtained and discussed and make a comparison with the round graphene with H atoms. Then we construct a electronic transmission model of the round shape graphene with Au atom line. Using the non-equilibrium Green function method, we calculate out the electronic transmission spectrum and density of states.In chapter V, the first principles calculations based on the density functional theory and the generalized gradient approximation are carried out on the pristine and boron-doped triangular graphene, and make a comparison between them.In chapter VI, make a conclusion of this paper, the main research results are listed. Because of the limitation of time, we did not refer to electronic properties of various graphene, at last, the direction of further research was pointed out.