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Since 2004 , Novoselov successfully fabricated graphene has attracted the world's climax , because of its unique structure and physical properties . Graphene has the perfect lattice structure , small size , and the characteristics of the quantum size effect , it has a lot of the peculiar nature of the carrier mobility , such as fast , high strength , good thermal properties , has been seen as alternatives to silicon , used to make supercomputers , space cable is the most potential of the new material . Graphene graphene research in the future life , science and technology has a very important significance in the industry, the electronics industry has a very broad application prospects . The graphene sheets for different computational simulation , their electronic properties , including the molecular geometry of the structural deformation of the influence of the molecular orbital, spectroscopy and electron transport characteristics . The main structure of the article is as follows: the first chapter mainly describes the physical properties of graphene and Research , and the graphene preparation methods do a simple introduction . The second chapter , specifically describes the theoretical basis for calculation in this paper , including ab initio methods , semi-empirical molecular orbital method , density functional theory and the nonequilibrium Green function , and computational tools to do a simple introduction . Chapter III , using the density functional theory B3LYP method and 6-31G (d) basis set level and pentacene molecule level , track density , infrared and Raman spectroscopy , and its stability theory . Chapter B3LYP method of density functional theory , circular graphene sheets in the 6-31G (d) basis set level , including the geometric structure , the frontier orbitals Millikan charge and spectral analysis , and hydrogenation circular graphene sheet to a certain extent do the comparison. Finally , we constructed a circular graphene sheet electron transport model of the electronic transmission and the density of states . Chapter V , using first-principles density functional theory and the generalized gradient approximation method , boron-doped and undoped triangular graphene sheets theoretical calculations , compared graphene changes in the electronic properties of boron-doped . Chapter VI summarizes the content of the full text of the study , due to time constraints , can not be comprehensive the various graphene 's electronic properties , and finally on the outlook for the post - work .
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