The Interficial Effect On The Electronic Structure Of Graphene And Silicene

Interface plays a very important role in the performance of materials.Because of the existence of the interface,the charge distribution at the interface is obviously different from that of bulk materials.Therefore,it has a very important influence on the electronic properties,transport properties,chemical adsorption,mechanical properties and anisotropy of materials.The interface design materials gradually become the important means of regulating the material properties,especially in the two-dimensional material,design of interface structure is to improve the photocatalytic properties,an important means of storage performance.This thesis is mainly based on the first principle as a means of electronic properties of C₂ N and graphene heterojunction and the small angle grain boundary structure of silicene.The main the conclusions are as follows:First,by using the first principle calculations,we systematically studied the electronic structure characteristics of graphene and C₂ N composed of interlayer heterostructure（Van Der Waals heterostructure）and in-plane heterojunction.The calculated results show that the band gap of graphene is open in these two kinds of heterostructure.For the interlayer heterostructure,the band gap of graphene is caused by symmetry breaking,and the band gap can be controlled by adjusting the interlayer spacing.For the in-plane heterostructure,the band gap of the graphene is induced by the quantum confinement effect,and the band gap decreases with the increase of the width of grapheme.These results indicate that C₂N/G heterojunctions can be used not only for the fabrication of high-performance FETs electronic materials,but also for photocatalytic water splitting.Second,using the first principle,we discussed the grain boundary（GB）silicene model.In particular,when the angle between the vector （?） and the vector （?） is 60 degrees,a class of seamless grain boundaries will be formed.Calculation shows that the formation energy of such seamless grain boundaries has no relation with the shape and direction of the cell,and depends only on the width of the grain boundaries,and is directly proportional to the width.Finally,by using the first principle simulation of the STM image of the grain boundary,found hat the brightness of the atoms at the crystal face is obviously higher than that of other atoms.STM simulations help experimental observers identify seamless grain boundaries.