Ⅲ-V族化合物GaInP是一种高效发光材料.金属有机化学气相沉积(Metal Organic Chemical Vapor Deposition,MOCVD)技术能均匀生长多结、多层和大面积的薄膜材料,是一种非常有效的方法.通过分别运用计算流体力学、动力学蒙特卡罗方法与虚...Ⅲ-V族化合物GaInP是一种高效发光材料.金属有机化学气相沉积(Metal Organic Chemical Vapor Deposition,MOCVD)技术能均匀生长多结、多层和大面积的薄膜材料,是一种非常有效的方法.通过分别运用计算流体力学、动力学蒙特卡罗方法与虚拟现实技术相结合,提出了一个研究垂直MOCVD反应器的GaInP薄膜生长过程的流体动力学、热力学和分子动力学多尺度模拟方法.可视化结果不仅准确和直观的显示了MOCVD反应器里的气体热流场分布情况,而且展示了MOCVD反应器中的GaInP薄膜生长过程.因此,该模拟为我们优化GaInP的MOCVD生长提供了一个重要指导.展开更多
根据钙钛矿结构的特点,提出了一种基于双格子系统的动力学蒙特卡罗KMC方法(kinetic monte carlo)。与传统的SOS(solid-on-solid)模型不同,该方法从单个原子事件出发,模拟沉积原子在表面的吸附、扩散和成键的动力学过程。应用该方法模拟...根据钙钛矿结构的特点,提出了一种基于双格子系统的动力学蒙特卡罗KMC方法(kinetic monte carlo)。与传统的SOS(solid-on-solid)模型不同,该方法从单个原子事件出发,模拟沉积原子在表面的吸附、扩散和成键的动力学过程。应用该方法模拟了BaTiO3薄膜在(001)面的同质外延生长过程,分析沉积原子动能对BaTiO3薄膜生长过程中形核率、岛密度、三维形貌、缺陷率以及成键率的影响,为优化工艺参数、制备高性能铁电薄膜提供依据。展开更多
Recently, we proposed the extended phenomenological kinetics (XPK) method, which overcomes the notorious timescale separation difficulty between fast diffusion and slow chemical reactions in conventional kinetic Monte...Recently, we proposed the extended phenomenological kinetics (XPK) method, which overcomes the notorious timescale separation difficulty between fast diffusion and slow chemical reactions in conventional kinetic Monte Carlo (KMC) simulations. In the present work, we make a comprehensive comparison, based on the newly developed XPK package, between the XPK method and the conventional KMC method using a model hydrogenation reaction system. Two potential energy surfaces with different lateral interactions have been designed to illustrate the advantages of the XPK method in computational costs, parallel efficiency and the convergence behaviors to steady states. The XPK method is shown to be efficient and accurate, holding the great promise for theoretical modelling in heterogeneous catalysis, in particular, when the role of the lateral interactions among adsorbates is crucial.展开更多
本文在分析表面扩散各向异性、二聚体和二聚体列影响的基础上,建立了Si(100)-(2×1)表面上Si薄膜生长的K inetic Monte Carlo(KMC)模型,利用该模型对薄膜生长的初始阶段进行了研究。结果表明:吸附原子的扩散距离随温度的变化满足指...本文在分析表面扩散各向异性、二聚体和二聚体列影响的基础上,建立了Si(100)-(2×1)表面上Si薄膜生长的K inetic Monte Carlo(KMC)模型,利用该模型对薄膜生长的初始阶段进行了研究。结果表明:吸附原子的扩散距离随温度的变化满足指数函数L=L0AeT/C。在一定的入射率下存在一最佳成岛温度,该温度随入射率的增大而升高。随入射率的减小,薄膜逐渐从离散生长向紧致生长转变,表面扩散的各向异性越显著。展开更多
The oscillation behavior of a two-dimension lattice-gas Brusselator model was investigated. We have adopted a coarse-grained kinetic Monte Carlo （CG-KMC） procedure, where m×m microscopic lattice sites are group...The oscillation behavior of a two-dimension lattice-gas Brusselator model was investigated. We have adopted a coarse-grained kinetic Monte Carlo （CG-KMC） procedure, where m×m microscopic lattice sites are grouped together to form a CG cell, upon which CG processes take place with well-defined CG rates. Such a CG approach almost fails if the CG rates are obtained by a simple local mean field （s-LMF） approximation, due to the ignorance of correlation among adjcent cells resulting fl＇om the trimolecular reaction in this nonlinear system. By proper incorporating such boundary effects, thus introduce the so-cMled b-LMF CG approach. Extensive numerical simulations demonstrate that the b-LMF method can reproduce the oscillation behavior of the system quite well, given that the diffusion constant is not too small. In addition, the deviation from the KMC results reaches a nearly zero minimum level at an intermediate cell size, which lies in between the effective diffusion length and the minimal size required to sustain a well-defined temporal oscillation.展开更多
基金supported by the Science and Engineering Research Council through Grant(152-70-00017)Use of Computing Resources at the A*STAR Computational Resource Centre and National Supercomputer Centre,Singapore
文摘Ⅲ-V族化合物GaInP是一种高效发光材料.金属有机化学气相沉积(Metal Organic Chemical Vapor Deposition,MOCVD)技术能均匀生长多结、多层和大面积的薄膜材料,是一种非常有效的方法.通过分别运用计算流体力学、动力学蒙特卡罗方法与虚拟现实技术相结合,提出了一个研究垂直MOCVD反应器的GaInP薄膜生长过程的流体动力学、热力学和分子动力学多尺度模拟方法.可视化结果不仅准确和直观的显示了MOCVD反应器里的气体热流场分布情况,而且展示了MOCVD反应器中的GaInP薄膜生长过程.因此,该模拟为我们优化GaInP的MOCVD生长提供了一个重要指导.
文摘根据钙钛矿结构的特点,提出了一种基于双格子系统的动力学蒙特卡罗KMC方法(kinetic monte carlo)。与传统的SOS(solid-on-solid)模型不同,该方法从单个原子事件出发,模拟沉积原子在表面的吸附、扩散和成键的动力学过程。应用该方法模拟了BaTiO3薄膜在(001)面的同质外延生长过程,分析沉积原子动能对BaTiO3薄膜生长过程中形核率、岛密度、三维形貌、缺陷率以及成键率的影响,为优化工艺参数、制备高性能铁电薄膜提供依据。
基金supported by the National Natural Science Foundation of China (No.21688102)the National Key Research and Development Program of China (No.2018YFA0208600)
文摘Recently, we proposed the extended phenomenological kinetics (XPK) method, which overcomes the notorious timescale separation difficulty between fast diffusion and slow chemical reactions in conventional kinetic Monte Carlo (KMC) simulations. In the present work, we make a comprehensive comparison, based on the newly developed XPK package, between the XPK method and the conventional KMC method using a model hydrogenation reaction system. Two potential energy surfaces with different lateral interactions have been designed to illustrate the advantages of the XPK method in computational costs, parallel efficiency and the convergence behaviors to steady states. The XPK method is shown to be efficient and accurate, holding the great promise for theoretical modelling in heterogeneous catalysis, in particular, when the role of the lateral interactions among adsorbates is crucial.
文摘本文在分析表面扩散各向异性、二聚体和二聚体列影响的基础上,建立了Si(100)-(2×1)表面上Si薄膜生长的K inetic Monte Carlo(KMC)模型,利用该模型对薄膜生长的初始阶段进行了研究。结果表明:吸附原子的扩散距离随温度的变化满足指数函数L=L0AeT/C。在一定的入射率下存在一最佳成岛温度,该温度随入射率的增大而升高。随入射率的减小,薄膜逐渐从离散生长向紧致生长转变,表面扩散的各向异性越显著。
文摘The oscillation behavior of a two-dimension lattice-gas Brusselator model was investigated. We have adopted a coarse-grained kinetic Monte Carlo （CG-KMC） procedure, where m×m microscopic lattice sites are grouped together to form a CG cell, upon which CG processes take place with well-defined CG rates. Such a CG approach almost fails if the CG rates are obtained by a simple local mean field （s-LMF） approximation, due to the ignorance of correlation among adjcent cells resulting fl＇om the trimolecular reaction in this nonlinear system. By proper incorporating such boundary effects, thus introduce the so-cMled b-LMF CG approach. Extensive numerical simulations demonstrate that the b-LMF method can reproduce the oscillation behavior of the system quite well, given that the diffusion constant is not too small. In addition, the deviation from the KMC results reaches a nearly zero minimum level at an intermediate cell size, which lies in between the effective diffusion length and the minimal size required to sustain a well-defined temporal oscillation.
