多元纳米薄膜生长界面的动态演化规律及其对微结构与性能的影响

In the work proposed herein, we shall investigate the evolution of the growing interface during the growth of multicomponent nanofilms as well as its influences on microstructure and various mechanical and functional properties through non-equilibrium molecular dynamics simulations and experiment. Specifically, the work is targeted at completing the following tasks and objectives: We shall first explore the influences of the evolution of growing interface on the microstructure of multicomponent nanofilms. By analyzing the dominant influencing factors and studying their effects on the evolution of the growing interface, the dependence of growing mode on film component and the surface properties of substrate will be determined. Through studying the role of temperature and electric field on the evolution of the growing interface under different specific conditions, the guideline to control the growth orientation and microstructure through adjusting temperature and electric field will be developed. In addition, the dependence of the sticking coefficient on temperature and component will be determined, and the feasibility of controlling the nanofilm growth in specific location and orientation through applying temperature gradient on substrate is also worthy to be explored. Finally, the relationship between microstructure and properties will be studied. This project is aimed at understanding the mechanisms of how the growing interface changes during multicomponent nanofilm growth, which will yield essential knowledge to control the growth processes and provide helpful information for the design and fabrication of functional nanofilms.

针对多元薄膜制备中由生长界面的不规则演化而引起的高缺陷率和生长不稳定等问题，本项目拟从微观角度通过分子动力学模拟并结合实验，系统的研究多元薄膜生长界面的动态演化规律及其对薄膜微结构和性能的影响，主要内容包括：研究多元薄膜制备中生长界面的演化过程对微结构形成的影响；分析生长界面演化的主要影响因素并研究其影响规律，确定薄膜的生长模式对组分和基片表面特性的依赖关系；研究温度、电场等物理场对生长界面演化的影响，明晰其对薄膜微结构以及生长取向的调控规律；确定生长温度、组分对沉积原子吸附系数的影响，分析由温度控制薄膜定位定向生长的可行性；探索多元薄膜的微结构与性能关联。本项目旨在揭示纳尺度薄膜生长界面的动态演化规律和机理，为降低缺陷率、控制生长不稳定性以及从原子尺度设计与制备纳尺度功能薄膜提供科学依据。

本项目从微观角度通过分子动力学模拟并结合实验，系统研究了多元薄膜生长界面的动态演化的主要影响因素并研究其影响规律，并取得了以下成果：获取了沉积速率对多元薄膜生长界面表面特性的影响规律，明晰其与生长温度共同主导薄膜生长模式的物理机制。阐明了沉积温度对薄膜生长过程中原子空间结构的调控机制，确定由生长温度来调控薄膜生长模式和生长取向的基本原则。获得了吸附系数对温度、组分以及沉积速率的依赖关系，提出多因素交互作用下多元纳米薄膜沉积生长的优化条件。综合上述结果，本研究阐明了多元纳米薄膜沉积生长界面的演化规律，揭示了复杂条件下多元纳尺度薄膜生长中的新规律和新现象以及背后所隐含的物理机制，并成功将其用于指导功能纳米薄膜制备的工程实践中。