Molecular Dynamics Simulation Of Graphene Ion Irradiation

Graphene is a two-dimensional material with a single atomic thickness and obtained the first stable sample in 2004.Many of the properties of graphene are excellent,as it is one of the most mechanically strong known materials,and it has very high conductivity and thermal conductivity.However,the band gap width of graphene is 0,which limits its application in electronic information industry.In order to improve the properties of graphene materials,we need to modify the structure of graphene.And because graphene is a two-dimensional material,the method used must be accurate enough to fine-tune the level of one atomic structure at a time.Irradiation of graphene with ions can meet such a requirement.So studying the radiation response of graphene will help deepen our understanding of the material.In this paper,the effect of ion irradiation of graphene is studied in detail.Different control conditions are used to apply different irradiation conditions(including irradiation intensity,irradiation density and irradiation dose)to different graphene objects(including single-layer suspended graphene,double-layer suspended graphene,single-layer graphene on Cu substrate,and double-layer graphene on Cu substrate),and the results(including graphene sputter atom number,defect area and number of complex defects,etc.)are calculated after the end of irradiation simulation.In the simulation process of graphene irradiation,the main factors affecting the formation of vacancy defects in graphene are theoretically analyzed,including graphene surface temperature,irradiation ion velocity and radiation density.Then we find that the number of vacant atoms is independent of the surface temperature of graphene,but is inversely proportional to the velocity of incident ions.Meanwhile,with the increase of incident ion density,the number of vacant atoms will increase first and then decrease.For this phenomenon,this chapter makes a hypothesis of the effective range of incident ions,which reasonably explains the previous simulation results.Finally,based on the research results,a method to guide the design of graphene radiation parameters is proposed.After studying the effect of ion irradiation on suspended graphene,the role of Cu substrate in the irradiation of graphene was further discussed.In the simulation,we found that graphene on Cu substrate exhibited four characteristics: increased damage threshold,reduced number of sputtered atoms,increased defect area,and increased number of complex defects.Based on these characteristics,this paper summarizes the two major roles played by the substrate in the process of graphene ion irradiation: shielding effect and increasing interaction between atoms.At the same time,in the irradiation simulation of double-layer graphene,we found that the effect of the substrate on graphene is slightly larger than the interaction between graphene layers.At the end of this article,a brief summary of the work of the full text is made.