原子级平整氧化物表面与界面的有序结构设计及其调控机制研究

表界面结构是决定纳米材料性能的关键因素，在原子尺度调控出规则的材料表面与界面，对于表面原位催化反应、半导体物理等表界面科学研究具有重要意义。通过高温退火法和薄膜外延生长处理氧化物衬底可以形成原子级平整表面与界面结构，但是表界面形成机制仍待系统研究。本项目选取不同晶格常数的氧化物作为单晶衬底以及两种不同晶体结构的氧化物作为外延薄膜。通过表面形貌、成分以及表面能测试，分析外界环境调控参数对衬底表面原子排布的影响规律，建立表面原子排布与表面能之间的关系，基于动力学蒙特卡洛模拟方法，揭示衬底表面原子的重排机制。针对原子级平整氧化物衬底与外延氧化物薄膜之间的晶格失配问题，通过建立宏观薄膜应力与微观原子级别相界面组成之间的联系，系统研究晶格失配程度与外延薄膜厚度，表面应力之间的关系与规律，掌握原子级平整氧化物薄膜的界面调控方法。研究结果将为精细调控原子级平整氧化物表面与界面结构提供实用的指导。

Surface and interface structure are the key factor to determine the properties of nanomaterials. Regulating the surface and interface of materials at the atomic scale is of great significance for surface and interface scientific research such as in situ catalytic reaction, semiconductor physics. The atomically flat surface and interface structure of oxide substrates can be obtained by high temperature annealing and film epitaxial growth, but the mechanism of surface and interface formation remains to be systematically studied. In this project, oxides with different lattice constants are selected as single crystal substrates and oxides with two different crystal structures are selected as epitaxial films. Through surface morphology, composition and surface energy tests, the influence of environmental parameters on the surface atomic configuration of the oxide substrate will be analyzed, and the relationship between surface atomic configuration and surface energy will be established. Based on the dynamic Monte Carlo simulation method, the atomic rearrangement mechanism on the surface of the substrate will be revealed. Aiming at the problem of lattice mismatch between the atomically flat oxide surface and the epitaxial oxide film, the relationship and law between lattice mismatch degree and epitaxial film thickness as well as surface stress will be systematically studied by establishing the relationship between macroscopic film stress and microscopic atomic-level phase interface composition. And the interface control method of atomically flat oxide film will be mastered. The results will provide practical guidance for fine-tuning the surface and interface structure of atomically flat oxides.