基于光催化效应的硬脆晶体超光滑无损伤表面高效创生机理及形貌控制研究

High performance optical and electrical components are important basic components for modern high-end equipment, and sub-nanometer scale processing techniques are required to ensure the realization of their significantly new features different from the conventional parts. At present, low-cost, high-efficiency, ultra-precision and damage free manufacturing of high performance optical and electrical components is the technological bottlenecks for their wide applications. In the pre-research of this project, energetic nanoparticles have been utilized to efficiently and controllably remove the surface material of brittle crystals at an atomic scale based on photocatalytic effects, and this achievement provided a theoretical basis for efficiently machining ultra-smooth and damage free surface, while the new physical and chemical phenomenon during this processing and their control method require further research. Therefore, this project plans to study the microscopic forming mechanism of the active interfacial reaction center on the nanoparticles that are excited by photon, and grasp the atomic-scale material removal regular pattern and control methods of the interface between the energetic nanoparticles and brittle crystals. On this basis, accurate cross-scale trend forecasting model and parameter model to accurately describe the morphology evolution of the ultra-smooth and damage free surface will be established, and the morphology evolution law will be grasped. Finally, an optimization process parameter model will be established for complex freedom ultra-smooth and damage free surface manufacturing based on experimental data, sub-nanometer scale precision control of surface quality and surface accuracy for machining ultra-smooth and damage free brittle crystals surface will be achieved in this study. The research achievements of this project will contribute significantly to the advanced development and innovation of effective manufacturing technology for polishing ultra-smooth and damage free surface.

高性能光、电元器件是现代高端装备的重要基础部件，需要亚纳米尺度的加工技术来保证其与常规零件显著不同的新特性。目前高性能光、电元器件的低成本、高效率、超精密、无损伤制造技术的不足是制约其广泛应用的瓶颈。申请人在前期研究中采用基于光催化效应的荷能纳米颗粒实现了硬脆晶体材料原子尺度高效去除，为超光滑无损伤表面的高效制造奠定了基础，但该过程中伴随的新物化现象及其控制技术还需进一步深入研究。因此本项目计划对纳米颗粒受光子激发生成界面反应活性中心的微观机制进行研究，掌握其与硬脆晶体界面间的原子尺度材料迁移机理及其控制方法。在此基础上建立精确描述超光滑无损伤表面形貌演化的跨尺度趋势性预测模型及参数模型，掌握其形貌演化规律。最后根据实验数据建立面向复杂自由曲面超光滑无损伤制备的工艺参数优化模型，实现表面质量与面形精度的亚纳米级精确控制。开展本项研究将有力促进我国超光滑表面高效制造技术的创新和发展。

以催化光场与射流动压场耦合作用下纳米颗粒的动力学行为对超光滑无损伤表面加工的动态作用机制为核心，建立了光催化纳米颗粒胶体射流加工材料去除过程的量子化学模型并进行了催化光场与射流动压场耦合作用下TiO2团簇与单晶硅典型表面模型相互作用的第一性原理仿真计算。结果显示：TiO2团簇在单晶硅表面吸附时形成新的Ti-O-Si共价键，其中凸峰体系在吸附过程中释放的能量最多，脱附时背键Si-Si键最容易断裂，平面体系释放的能量次之，脱附时O-Si键最容易断裂，凹谷体系在TiO2团簇吸附过程中释放的能量最少，脱附时消耗的能量最大，Ti-O键相对最容易断裂。三相微射流流体动力学仿真结果显示，相同情况下余弦形光-液耦合喷嘴较锥柱形光-液耦合喷嘴可获得更大的射流速度、动压力和静压力，抛光效率更高。在此基础上进行了TiO2纳米颗粒与单晶硅表面吸附的实验研究，红外光谱及光电子能谱结果显示在TiO2纳米颗粒与单晶硅表面吸附过程中确有新的Ti-O-Si共价键生成；在紫外光诱导纳米颗粒胶体射流抛光系统上进行了超光滑表面抛光的系列实验，获得了表面粗糙度Rq0.4nm，Ra0.3nm的亚纳米级超光滑表面，截面分析及功率谱密度结果显示表面存在的纳米波纹（纵横尺寸100nm×100nm，PV值±1nm）对工件表面0.08~0.3μm空间波段内的功率谱密度存在较大影响。