Different Elements Of Saturated Graphene Nanobelts, The Primary Principle Of Research

Since Andre Geim Study group of university of Manchester in England found grapheme in2004,graphene has been widely studied in recent years．Due to its novel properties，for example,Mechanical properties, thermal properties, optical properties,especially a number of exotic properties,such as electronic bizarre quantum hall effect, abnormal local area of Effect, high Mobility carriersand so on.Graphene application prospect is very wide; it can be used as a transparent conductive film touchpanel, high-speed graphite surfaces and optical element, and solar cells.This paper is divided into five chapters, the first chapter gives a simple introduction of thediscovery, and the special electronic structure, special nature, focus on the introduction of thegraphene transport properties, such as graphene bizarre hall effect, abnormal wear the tunneling effect,etc. Then we present the experimental techniques to produce grapheme and graphene applicationprospect. Preparation methods include physical method and chemical method, and we also introducethe advantages and disadvantages of the two methods.The second chapter presents the research status of the grapheme. This is mainly aimed atgrapheme nano-ribbons research results, through different methods for the nature of nano-ribbionswith different edge-shapes study; graphene storage hydrogen, and applying different transverseelectric field cause the nature change of the graphene.The third chapter presents the basic content of the first principle and density functional theory.There are three primary principle of approximate, the Non-relativistic approximate,Born-Oppenheimer approximation, and the single particle approximation, the article gives adetailed introduction of the three types of approximate. The basic idea of density functional theory issimplified many electronic system to be single electronic problems with electronic density as basicvariable. The theory is completely based on quantum mechanics to reduce computation cost. Indensity functional theory, we introduces Kohn-Sham equation, and the methods of processingcommon exchange association-LDA and GGA, finally, simple introduction to the software we use. The fourth chapter research graphene nano-ribbon’s electronic distribution and conductiveproperties modified with different elements and absorbed different concentrations F atoms indifferent locations.First study the conductive properties of different width of the graphenenanoribbon.We found that different width of the zigzag graphene nanoribbon is conductors andarmchair graphene nanoribbon is semiconductor, and with different width, the band gap is different.Then saturate the boundary of zigzag graphene nanoribbon with Fe, F, Br, Cl, get state density figure,and energy band diagram to analyze these elements on the influence of graphene nanoribbon’sboundary electronic. After saturated with the same elements on the border,the system’s conductivitysystem will occur transform. Saturated with F is semiconductor system, and the band gap is not verybig, with Fe, Br, Cl saturated is the conductor. With different elements saturated can cause the energyband degenerate and remove. Then discussed the armchair graphene nanoribbon adsorbed with thesame concentration of F atoms, and different positions of F lead to the system’s band gap is different.The system with the biggest energy gap when F atomic adsorbed on the boundary. The systemadsorbed different concentration of F atoms with different energy band gap, and concentration of theatoms F is bigger,energy band gap is bigger also.Conclusions and outlook are given in chapter5．...