Ion Irradiation On The Effect Of Thermal Conductivity Of Graphene

As a typical two-dimensional material, graphene has excellent strength, heat,light, electricity and magnetic properties, it has been one of the most popular materials in condensed matter physics and materials since prepared successfully in2004. Many properties of graphene can be modulated by applying an external field,stress, quantum cutting and nano-composite. Based on various modulation means to enhance its performance is an important direction of their research. Among them, the electric heating and other properties of graphene are studied by means of the defect,that is so-called defect engineering, It's a hot spot in the field of condensed matter. In this paper, the non equilibrium molecular dynamics method is used to study the effect of defects on the thermal properties of graphene. First, by the ion irradiation to form structural defects, we studied the laws of defects formation and the defects influence on thermal conductivity of graphene on the basis of this study, then further developed the modulation rules between the energy, dose, incident angle of irradiation ions and the thermal conductivity. We mainly carried out the following work:(1)Relationship between irradiation energy and formation of graphene defects.First, we used single ion to irradiate graphene, along with the change of energy of incident ions, there are appeared four events randomly: adsorption, rebound,shortcomings and traditional. By statistical study of a large number of incident events,we get the relationship between the probability of the incident ions' energy and four events.(2)The effects of different ion irradiation dose on the thermal conductivity of graphene. The simulation results show that for anyone certain energy of the incident ions, the thermal conductivity of graphene is reduced with the increasing dose of incident ions. And with the increasing energy of ions, the effect of the thermal conductivity of graphene is very similar for different dose of incident ions. It is closely related to the number of adsorption of atoms and defects(including rebound and penetration events on the graphene strip does not affect) for the increase or decrease of thermal conductivity of graphene. Our calculations also show that both the adatom defects or vacancies, the thermal conductivity is increased quickly at first,then decreased slowly, and for the same concentration of adsorbed atomic defects and vacancy defects, vacancies are more obvious restraining the thermal conductivity of graphene.(3) The effect of different radiation angles on the thermal conductivity of graphene. We studied the relationship between different incident angles and thermal conductivity. In this article, with the increasing of incident angle of the ions, the number of defects in graphene is increased, then the thermal conductivity decreased slowly, but this decrease is not linear. When the angle is larger than 60°, the number of damage reduced gradually, then thermal conductivity was rising rapidly. We can well explain the complex relationship between the thermal conductivity of graphene and the energy and incident angle of incident ions using the relationship between the probability of defects and the energy of incident ion.