【作者】 王利琴；

【导师】 王利光；

【作者基本信息】 江南大学 ， 光学工程， 2010， 硕士

【摘要】 自2004年,Novoselov成功的制备出石墨烯,由于其独特的结构和物理性质已经引起了全世界的研究高潮。石墨烯具有完美的晶格结构,体积小,量子尺寸效应等特性,决定了它有很多奇特的性质,如极快的载流子迁移率,高强度,良好的热学性质等,已经被看作硅的替代品,用来制造超级计算机,太空电缆,是最具有潜力的新型材料。石墨烯在工业,电子行业都有很广阔的应用前景,因此对石墨烯的研究在将来的生活,科技有很重要的意义。本文主要针对不同的石墨烯片进行计算模拟,研究了它们的电子特性,主要包括分子几何结构形变对分子轨道、光谱和电子传输特性等的影响。文章的主要结构如下:第一章,主要介绍了石墨烯的物理特性和研究现状,并对石墨烯的制备方法做以简单介绍。第二章,具体介绍了本文计算的理论基础,包括从头算方法、半经验分子轨道方法、密度泛函理论和非平衡格林函数等,并对计算工具做了简单的介绍。第三章,采用密度泛函理论的B3LYP方法,在6-31G(d)基组水平上对并六苯环的分子能级,轨道密度,红外和拉曼光谱及其稳定性进行了理论研究。第四章,采用密度泛函理论的B3LYP方法,在6-31G(d)基组水平上对圆形石墨烯片进行了研究,包括几何结构、前线轨道、密立根电荷和光谱分析,并与加氢圆形石墨烯片在一定程度做了比较。最后我们构建了圆形石墨烯片的电子输运模型,对电子传输和态密度进行了研究。第五章,采用密度泛函理论和广义梯度近似的第一性原理方法,对硼掺杂和未掺杂三角形石墨烯片进行理论计算,比较了石墨烯进行硼掺杂后的电子特性的改变。第六章,总结了全文的研究内容,由于时间的限制,不能全面的研究各种石墨烯的电子特性,最后提出对后期工作的展望。更多还原

【Abstract】 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.更多还原