Interfacial Thermal Transport Characteristics Of Black Phosphorene/Molybdenum Disulfide Vertical Heterostructures Based On Molecular Dynamics Simulations

The development of electronic devices towards miniaturization and integration makes the thermal management problem has become one of the bottlenecks in the electronic devices.In addition,new vertical heterostructures have been synthesized experimentally to meet the requirements of spatial structure and performance of the electronic devices in actual operation.Currently,vertical heterostructures are attracting a lot of research attention due to their outstanding physical properties and are considered as an alternative to next-generation nano-electronic devices.The interfacial thermal transport properties play an important role in their practical applications for vertical heterostructures.In this paper,molecular dynamics is used to investigate the effects of different temperatures and four different elemental vacancy defects and their defect concentrations on the thermal transport properties of the BP/MoS₂ vertical heterostructure interface.The main contents and results of the study are as follows:1.In this paper,the BP/MoS₂ vertical heterostructure was constructed for the first time by programming means,and the in-plane thermal conductivity of the BP/MoS₂ vertical heterostructure was calculated using a non-equilibrium molecular dynamics method.In addition,the SW potential function describing the interatomic forces of MoS₂ using 12atomic types was used to solve the contradictory problems in the simulation process.2.In this paper,the values of the interfacial thermal conductance of BP/MoS₂ vertical heterostructure at different temperatures were calculated using the transient pumping probe method.The results of the calculations show that the interfacial thermal conductance of this vertical heterostructure increases with the increase of temperature.The changes are analyzed by theoretical means such as phonon density of states and phonon dispersion curves,whose theoretical analysis shows that an increase in temperature leads to enhanced low-frequency phonon modes,greater transmittance of low-frequency phonons,and a greater number of phonons passing through the interface,resulting in a temperature-dependent interfacial thermal conductance.3.In this paper,the BP/MoS₂ vertical heterostructure models of four vacancy defects（S vacancy,double S vacancy,Mo vacancy,and P vacancy）were constructed by programming means,and the interfacial thermal conductance of the BP/MoS₂ vertical heterostructure was calculated for the four vacancy defects and their different defect concentrations,and their calculation results showed that the S vacancy defects and double S vacancy defects have little effect on the interfacial thermal conductance.The Mo vacancy and P vacancy defects lead to defect concentration-dependent interfacial thermal conductance,with Mo vacancy defects having the greatest effect on interfacial thermal conductivity.The theoretical analysis shows that the PDOS image does not change significantly when there are S vacancies and double S vacancies in the heterogeneous structure system;when there are Mo and P vacancy defects in the system,the low-frequency phonon mode is enhanced significantly with the increase of the defect concentration,which leads to the increase of the number of phonons passing through the interface and the increase of the interfacial thermal conductance,which is consistent with the theoretical analysis and calculation results.In addition,the weakening of phonon localization in the range of 4～6THz is the reason for the more significant change of Mo vacancy defects on the interfacial thermal conductance,as shown by the phonon participation rate.