Molecular Dynamics Simulation Of The Thermal Conductivity Of Modified Single Wall SiC Nanotubes

As one of the silicon carbide materials,the SiCNTs?SiC nanotube?not only has the high temperature resistance and high pressure of the three generation wide band gap semiconductor materials,but also follows the electronic structure of the hexagonal nanotube.Since the advent of SiCNTs,some scholars have found that doping and vacancy will have a certain effect on the physical and chemical properties of SiC nanotubes.Because Si CNTs exhibits very high thermal stability at high temperature,it determines the bright application prospect of SiCNTs,and the thermal conductivity of SiCNTs has become a research hotspot.However,because the size is too small and the preparation process is complex,it is difficult to use the experimental method to measure the thermal conductivity of SiCNTs.Therefore,this paper is devoted to the prediction of the thermal conductivity of the substitutional,vacancy and bond fractured modified SiCNTs by using the nonequilibrium molecular dynamics method.?1?The substitutional modified SiCNTs:The system temperature is 300K,and thesubstitutional atom is selected for the two atoms of N and P.The doping percentage change in the range of 0-0.104%,N/P atom's modification for SiCNTs thermal conductivity's range are 74.057-82.904Wm^-1K^-11 and 70.3232-82.904Wm^-1K^-1;the doping percentage is0.052038%,the system temperature is in the range of 10-600K,N/P atom's modification for SiCNTs thermal conductivity range are:69.7460-75.8920Wm^-1K^-1,67.823-75.867Wm^-1K^-1.P atom for a heat conduction modified SiCNTs was less than N atom for a SiCNTs rate,the greater the dopingpercentage is,the smaller the thermal conductivity is;the higher the temperature is,the bigger the phonon thermal motion intensities are,and thermal conductivity is larger;apercentage of the total number of atoms of different doping atoms under different phonon scattering probability,the percentage of the total the atomic number of impurity doping atoms increases,phonon and impurity scattering probability between the greater inhibition of energy transmission,thermal resistance is larger and the thermal conductivity is smaller.?2?Single space and single band fracture modified SiCNTs:At room temperature,the variation range of tube length is between 13.01-78.15nm,and the range of thermal conductivityofSiCNTsis34.725-76.821Wm^-1K^-1?bondbandfracture?and31.668-76.602Wm^-1K^-1?Dan Kongwei?.The range of temperature variation range is 10-700K,and the change range of the thermal conductivity of the vacant modified SiCNTs with the length of 65.05nm is 67.3220-70.7460Wm^-1K^-1?bond fracture?and 66.283-70.222Wm^-1K^-1?single vacancy?.Vacancy and band break modification is a kind of static scattering factor,which reduces the mean free path of phonons.The size effect is more obvious when the tube length is smaller than the mean free path of phonons.When the tube length of Si CNTs is larger than that of its phonon mean free path,the thermal conductivity increases sharply.This indicates that the effect of tube length on the thermal conductivity of SiCNTs is greater than that of vacancy and bond band breakage.The research in this paper provides some reference for the further understanding of the thermal transmission properties of the doped SiC nanotubes.