纳米材料制备及物性测量的虚拟过程工程初探

Explorations to the virtual process engineering offabrication and property measurement of nanomaterials

分子模拟方法和高性能计算的进展为材料领域的虚拟过程工程提供了可能,即可以从微观层面以可视化和在线交互的方式复现并虚拟操控一些纳米材料的完整制备过程并全面测量其机械和热力学性质。本文以晶硅气相化学沉积过程和硅纳米线导热系数的预测为例,探讨并初步展示了这种可能性。文章表明:通过单独调控反应、扩散两种主要控制机制可以揭示它们的竞争协调对所制备的晶体结构与形貌的影响,为其定向调控提供指导与依据;通过大规模的原子模拟,可以直接获得微米以上尺度的硅、碳等材料的机械和热力学性质,克服有限尺寸效应。材料虚拟过程工程的最终实现将为其构效关系的机理研究和优化设计与制备调控提供强有力手段。

The development of molecular dynamics simulation and high performance computing has provided the possibility of virtual process engineering （VPE） in the field of materials, that is, the reproduction and virtual manipulation of the complete fabrication processes and comprehensive measurement of their mechanical and thermal properties. This possibility is explored in silicon crystallization via chemical vapor deposition and the measurement of its thermal conductivity. It was demonstrated that reaction and diffusion rates can be adjusted separately in VPE and the compromise in competition of these two mechanisms results in different structure and morphology of the silicon materials, which could be the basis and guidelines for their design and fabrication. With large-scale atomistic simulation, the mechanical and thermal properties of materials such as silicon and carbon can be measured directly at micron scales and beyond, overcoming the finite size effect in previous simulations. The final realization of VPE will provide a very powerful tool for under-standing the structure-dependent effects and optimal design of many materials.