Electrical Properties Research Of Few-layer Graphene

Graphene is a graphite sheet structure,and is the important research object in the current material and condensed matter subjects.Since its first preparation in 2004,it has received extensive attention and research in theory and experiment.Due to its excellent properties,graphene has been applied in many fields.Unlike most two-dimensional materials,graphene is a zero band gap semiconductor.Therefore,graphene is applied to electronic devices with relatively small switches.So there is an important issue to be solved urgently: how to open and control the band gap of graphene.In this paper,the CASTEP module of Materials Studio is used to calculate the electrical properties of A-A and A-B symmetric few-layer graphene,respectively.The main research content of this paper are as follows:Firstly,this thesis briefly introduce the research background and nature of graphene.The preparation methods of graphene and the main applications in the industrial production are also listed.The origin,research contents and significance of the project are also described.Secondly,the brief description of the first-principles and the theoretical basis of the density functional theory are introduced,for instance,Hohenberg-Kohn theory and Kohn-Sham function.The accuracy of the calculation is also improved by comparing the two density approximations and the two pseudopotopes used in the calculation.In addition,the calculation software CASTEP used to the study of few-layer graphene electrical performance is also introduced.Finally,the effect of the number of layers on the electrical properties of two symmetric graphene is discussed.Based on the monolayer graphene,the lattice parameters and energy of few-layer graphene are discussed with the change in the number of layers and symmetry.Considering scattering mechanism of few layer graphene structure,the change of the conductivity with thickness are analyzed.