微纳米尺度二维材料界面粘附能的原位电子显微学研究与调控

Along with the wide application of two-dimensional (2D) materials in important fields like micro/nano devices, micro/nano electromechanical systems and wearable devices etc., their interfacial adhesion energy has acted as the key parameter during device design and fabrication processes, as well as their performance evaluation process in various environment. However, there still lack of the quantitative and controllable measurement and modulation of the interfacial adhesion energy of 2D materials at the micro/nanoscale. To this end, with the help of in-situ electron microscopy technique, this project will firstly develop a novel method to realize the systematical measurement of adhesion energy between 2D material interlayers, 2D material heterostructures and 2D materials with different substrates. Based on this method, the influence of environmental factors including temperature, humidity and oxygen on the adhesion energy will be further elucidated. Furthermore, the working mechanism of these factors will be illustrated with the characterization of their microstructures, revealing the relationship between adhesion energy and the corresponding microstructures. Moreover, by changing the surface roughness, substrate potential and interlayer misfit angle of 2D materials, strategies and their effectiveness for the adhesion energy modulation will also be investigated. With the realization of the systematical measurement and modulation of the interfacial adhesion energy of 2D materials in various environment, this project can provide important experimental supportings for the design, fabrication, performance improvement and stability evaluation of 2D material-based micro/nano devices.

随着二维材料在微纳器件、微纳机电系统及可穿戴设备等多个重要领域的广泛应用，其界面粘附能已成为影响器件设计、制备过程及评价其在不同环境、负载下工作性能的关键参数。但目前对微纳尺度二维材料界面粘附能的系统测量和调控还比较欠缺。针对该问题，本项目拟借助原位电子显微学技术，探索实现微纳米尺度二维材料层间、异质结间及其与不同衬底间粘附能的定量可控测量方法。在此基础上，研究温度、湿度和氧气等环境因素对二维材料粘附能的影响，并通过结构表征深入探讨其影响机制，揭示二维材料界面粘附能与其微观结构的关系。并通过改变衬底粗糙度、电势及二维材料的层间转角等方式来探索实现二维材料界面粘附能调控的有效措施。该项目的开展不仅能实现不同环境负载下二维材料界面粘附能的系统测量和调控，还有望为基于二维材料的器件设计、制备、性能优化及可靠性评价提供重要的实验依据。

随着二维材料在微纳器件、微纳机电系统及可穿戴设备等多个重要领域的广泛应用，其界面粘附能已成为影响器件设计、制备过程及评价其在不同环境、负载下工作性能的关键参数。但目前对微纳尺度二维材料界面粘附能的系统测量和调控还比较欠缺。针对该问题，我们借助原位电子显微学技术实现了微纳米尺度二维材料层间粘附能的定量可控测量。通过采用连续介质力学模型分析了MoS2的剥离断裂过程，得到了MoS2的层间结合能与其杨氏模量、断裂强度和圆锥体几何参数的关系。实验结果表明机械剥离MoS2的层间结合能为0.55±0.13J·m-2，与理论计算结果（0.422 J·m-2）相近。该方法为二维材料的层间结合能的定量测量提供了一种普适方法。此外，聚焦二维材料基柔性器件的设计、制备及性能优化，我们还明晰了温度、电场、应变及碱性环境对其界面微结构的影响，并揭示了二维材料中所体现出的各项异性的力电响应。本课题的研究结果将为理解二维材料在外场作用下的界面结构及其微纳器件的设计、制备及应用提供重要的实验依据。