The Electronic Structure Of Silicene Nanoribbons:Two Edges Chemistry Modified And First-principles Study

With the innovation of technology, decrease of materials’ dimensions in electronic devices, the volatility is significant when the mater’s scale reduced to the nanometer scale. In 2004, Grahpene, which were successfully prepared in the lab, were found to have excellent properties. It upsurges a great interest on researching it in the scientific community. In the past ten years, people were expensive and in-depth research on the graphene and graphene-based materials, which include fullerenes, carbon nanotubes,graphene nanoribbons, etc. Moreover, they were always trying to application to those materials in electronic devices. However, electronic devices cannot directly use Grahpene because it is one kind of zero band gap semiconductors. Therefore, based on the existing silicon-based technology make people have great research interests on Silicene material. Silicene, which is a new material with a similar geometry of Graphene, has successfully prepared in lab recently. It can be well compatible with existing silicon-based technology, and it may be the most suitable materials that applied to modern electronic devices. Therefore, the application of nanomaterials Silicene electronic devices for cutting the material and determine its electrical properties is particularly important. It’s obviously that cutting Silicene or silicon nanotubes to get Silicene nanoribbons(Si NRs); different chiral edge will be two Silicene nanoribbons high symmetry structure: Zigzag Silicene nanoribbons(referred ZSi NRs) and Armchair Silicene nanoribbons(referred ASi NRs).This paper based on density functional theory(DFT), to study the electrical properties of zigzag nanoribbons Silylene(ZSi NRs), which mainly discuss the effects among different marginal modification, zigzag Silicene nanoribbons structures and electrical properties. The hydrogen(H), fluorine(F), hydroxyl(OH) and oxygen(O)were chosen on the serrated edge Silicene nanoribbons modification, and the difference of electron spin polarization direction, which is caused by exchanging and associating between the edge electrons, is considered. Therefore, zigzag Silicene nanoribbons exist Non-magnetic state(NM), the Ferromagnetic state(FM) and Anti- ferromagnetic state(AFM). First step is relaxation optimizing the serrated marginal Silicene nanoribbons after chemical modification in the geometry with three kinds of spin magnetic state.Second step is the calculations based on stable geometry, and obtained the energy banddiagram, the density of states and charge density map. The last step is studying its electrical properties, analyzing the reasons of electrical properties and conjecturing the method of changing the electrical properties.By studying this thesis to verify the geometry of the double zigzag Silicene nanoribbons that neighboring silicon atoms are not in the same plane with low-buckled geometry. Edge chemical modification of its geometry is not much affected by the structure of the edge stress small variations. Then its band structure diagram, the density of states and the charge density maps were analyzed, the results show that the localized states with edge chemical modification, affect their electrical properties, and open the energy band near the Fermi level when the polarization direction opposite antiferromagnetic.This thesis is divided into five chapters total, the first chapter introduces the density functional theory; second chapter introduces of Graphene, Silicene; The third chapter discusses the modification of the serrated marginal Silicene effect of structure;the fourth chapter is the impact on the serrated marginal Silicene charged properties of Silicene nanoribbons; the last chapter is a summary of this thesis.