CAREER: Understanding Strain and Strain Relaxation Mechanisms in Complex Two-Dimensional Materials

职业：了解复杂二维材料中的应变和应变松弛机制

• 批准号: 2239545
• 负责人: Yimo Han
• 金额: $ 65.07万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2239545&HistoricalAwards=false
• 关键词: CAREER; Understanding; Strain; Relaxation; Mechanisms

This Faculty Early Career Development (CAREER) award supports research to investigate how two-dimensional (2D) films deform to release strain, and how to leverage this knowledge to engineer new applications of 2D materials. Deformation mechanisms and defects play a critical role in the mechanical, electrical, and chemical properties of 2D materials due to their atomic thinness. However, a fundamental understanding of how strain relaxation in these materials differ from their bulk counterparts remains elusive due to challenges in characterization at multiple length scales. This project aims to develop new electron microscopy approaches to observe and understand novel strain relaxation mechanisms. The insights gained from this study will advance the use of complex 2D materials in flexible electronics, quantum computing, catalysis, and protective coatings. Additionally, the project will support several activities to support broader participation in STEM, with a focus on underrepresented minorities and women, including a Research Experience for Teachers program for local high school teachers, interactive science demonstrations for young learners in collaboration with a local museum, and integration of research and education through curriculum development.Conventional understanding of strain relaxation in bulk materials have not been successful in describing the deformation behavior of 2D materials and heterostructures. The central hypothesis of this project is that additional novel deformation mechanisms besides the traditionally observed dislocation-based mechanisms contribute towards stress relaxation in 2D materials. To investigate this possibility, this project will use state-of-the-art four-dimensional scanning transmission electron microscopy (4D-STEM) and related techniques to map the lattice strain and deformations in 2D heterostructures. By investigating various sizes and shapes of 2D epitaxial heterostructures, a comprehensive understanding of novel deformations mechanisms in complex 2D materials is expected. This knowledge will enable precise and predictable engineering of strain and defects in these materials and their heterostructures, with significant implications for the development of advanced devices. This project is jointly funded by the Mechanics of Materials and Structures (MoMS) program in the Division of Civil, Mechanical and Manufacturing Innovation (CMMI) and the Solid State and Materials Chemistry (SSMC) program in the Division of Materials Research (DMR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该学院早期职业发展（CAREER）奖支持研究二维（2D）薄膜如何变形以释放应变，以及如何利用这些知识来设计2D材料的新应用。由于二维材料的原子薄度，变形机制和缺陷在其机械、电学和化学性质中起着关键作用。然而，由于在多个长度尺度上表征的挑战，对这些材料中的应变弛豫如何不同于其散装对应物的基本理解仍然难以捉摸。该项目旨在开发新的电子显微镜方法来观察和理解新的应变弛豫机制。从这项研究中获得的见解将推动复杂2D材料在柔性电子、量子计算、催化和保护涂层中的应用。此外，该项目将支持多项活动，以支持更广泛地参与STEM，重点关注代表性不足的少数族裔和妇女，包括针对当地高中教师的教师研究经验计划、与当地博物馆合作为青少年学习者进行互动科学演示，以及通过课程开发整合研究和教育。对散装材料中应变松弛的传统理解还没有被成功地描述了二维材料和异质结构的变形行为。该项目的中心假设是，除了传统观察到的基于位错的机制之外，其他新的变形机制有助于2D材料中的应力松弛。为了研究这种可能性，该项目将使用最先进的四维扫描透射电子显微镜（4D-STEM）和相关技术来绘制2D异质结构中的晶格应变和变形。通过研究各种尺寸和形状的二维外延异质结构，在复杂的二维材料中的新的变形机制的全面理解是预期的。这些知识将使这些材料及其异质结构中的应变和缺陷的精确和可预测的工程，对先进器件的发展具有重要意义。该项目由土木、机械和制造创新部（CMMI）的材料和结构力学（MoMS）项目和材料研究部（DMR）的固态和材料化学（SSMC）项目共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。