Study On The Structure And Physical Properties Of Organic Materials Under Extreme High Pressure Or High Voltage

With the increasing application of organic materials,there are more and more applications in extreme environments such as high temperature,high pressure and high radiation.Conventional laboratory research methods cannot be well applied to material research in extreme environments,in addition to the long development cycles and high costs,it cannot be applied to the current research status.Material calculation simulations make up for the above shortcomings.Based on theoretical models and calculation predictions,material calculation simulation can comprehensively analyze the structure of materials.On the basis of theoretical models,the depth of traditional materials research has been expanded,and the combination of qualitative analysis and quantitative analysis has been realized;and calculation prediction has made the research of materials more directional,which has important significance for research innovation,it also further improves the efficiency of research work.This paper adopts the material calculation simulation method based on the material calculation theory and carries out the following three aspects of research:(1)Based on first-principles calculations based on density functional theory,the structure,electron and light absorption properties of IBO crystals in the pressure range of 0-300 GPa are studied.A comprehensive analysis of the changes in the lattice constant,bond length and bond angle of IBO crystals under high-pressure environments has revealed that the crystals have complex physical structure changes under different pressures.Then,the energy band structure and density of states of the IBO crystal are analyzed.The results show that the electronic characteristics of the IBO crystal changed between 120 and 150 GPa.The electronic structure of the IBO crystal become unstable with the increase of pressure,and at 180 GPa,it reverts to the metallic phase.In addition,the study of light absorption properties shows that as the pressure increases,IBO crystals have higher optical activity,and three significant phase transitions occur at 120,150,and 180 GPa,respectively.(2)Based on first-principles calculations based on density functional theory,the structure,electronic and light absorption properties of 6-Amino crystals under high pressure are studied.Analysis of the changing trends of lattice constants,bond lengths and bond angles under different pressures shows that the 6-Amino crystal undergoes complex physical structure changes under high pressure.Then the band gap,partial density of states and density of states of the 6-Amino crystal are analyzed,and it is found that the electronic properties of the 6-Amino crystal undergo four obvious phase changes within the pressure range of 100-280 GPa.In addition,the study of light absorption characteristics shows that with the increase of pressure,the optical activity of 6-Amino crystals is relatively high,and two obvious structural transitions are also observed at 100 GPa and 180 GPa.(3)This paper properly optimizes the structure of the traditional 1700 V SiC VDMOSFET.In the traditional structure,N-type doping is introduced into the JFET region,and P-type doping is introduced into the accumulation region.At the same time,based on Silvaco software,the JFET area width,the concentration and width of the N-type doping in the JFET area,and the concentration and width of the P-type doping in the accumulation area are simulated and optimized to determine the final structure.After the introduction of N-type doping,the breakdown voltage of the device has dropped,but it still meets the design requirements of 1700 V breakdown voltage.The electric field strength of the gate oxide layer is reduced by 0.165MV/cm,and the specific on-resistance is basically the same as the traditional structure;On the basis of this structure,the breakdown voltage of the device after the introduction of P-type doping is 1820 V,which meets the design requirements.Compared with the traditional structure,this structure slightly increases the specific on-resistance while further reducing the electric field intensity at the center of the gate oxide layer.Improve the reliability of the gate oxide layer.