Research On Thermal Conductivity Of ZnS Film Based On Molecular Dynamics Simulation

ZnS thin film materials are the emerging third-generation wide-bandgap semiconductors.They have two different structures,zinc blende structure and wurtzite structure.In general,zinc blende is more stable.Sphalerite zinc sulfide is widely used in many fields,such as photovoltaic devices,solar cells,etc.reason for its excellent physical and chemical properties.Electronic components can not avoid the generation of heat,and as the size of the device is gradually dominated by micro-nano,the heat transfer and heat dissipation problems of the device itself have become particularly prominent.In order to make the device performance more stable and reliable,and improve the thermal design and thermal management of the device,it is very important to carry out the research on the thermal conductivity of ZnS thin film materials.Since the theory of low-dimensional materials is still in conclusive,and experimental research is very difficult,it not only requires investment in very expensive equipment,but also time-consuming and laborious,computer simulation methods will be easier to implement,and can also reduce costs.This paper applies the non-equilibrium molecular dynamics method in the computer simulation method.At room temperature 300 K,the COMPASS force field is used to study the different film thicknesses and different vacancy concentrations under the NVE ensemble and periodic boundary conditions.Thermal conductivity of the ZnS thin film material under.The simulation results show that:When the thickness of the simulated zinc sulfide film is between 12.92nm-17.25 nm,the thermal conductivity value range is between 0.449742 W/(m?K)-0.620647 W/(m?K).The thermal conductivity of the zinc sulfide nano-film is significantly lower than that of the zinc sulfide body material,and there is a more obvious size effect.And the thermal conductivity of the zinc sulfide film increases with the increase of the film thickness.The reason for this result can be analyzed based on the aerodynamic theory.When the simulated film is more than ten nanometers,the mean free path of phonons is dependent on the simulated film thickness.When simulating a zinc sulfide film containing sulfur vacancies,the simulated film thickness is 15.08 nm.The thermal conductivity of zinc sulfide film containing sulfur vacancy defects is lower than that of pure crystal zinc sulfide film,and the vacancy concentration increases from 0.02790% to 0.08371%,and the thermal conductivity decreases from0.309075 W/(m?K)to 0.21721W/(m?K).The reason for this result is that the vacancy defects cause a change in the crystal lattice,thereby reducing the average free path,resulting in a smaller thermal conductivity value than the pure crystalline ZnS film.