Collaborative Research: Remote epitaxy on van der Waals materials: unveiling adatom interaction, growing single-crystal membranes, and producing unconventional heterostructures

合作研究：范德华材料的远程外延：揭示吸附原子相互作用、生长单晶膜以及产生非常规异质结构

• 批准号: 2240995
• 负责人: Sang-Hoon Bae
• 金额: $ 9万
• 依托单位: Washington 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: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2240995&HistoricalAwards=false
• 关键词: Collaborative; Research; Remote; epitaxy; van

PART 1: NON-TECHNICAL DESCRIPTIONScience and technology have developed alongside with discovery of new materials platform, such as carbon nanotubes, or synthetic polymers. Instead of chasing after a completely new materials, the research team targets a novel twist, making currently existing materials to become flatter, thinner, and lighter. Back in 2017, the principal investigator invented remote epitaxy, which allows growing nanoscale materials on graphene-coated templates to be exfoliated afterwards. These thin freestanding materials can become building blocks for lightweight, flexible devices having unprecedented performance. Until now, studies on remote epitaxy have been mostly limited to empirical observations on materials such as gallium nitride and gallium arsenide typically used in semiconductors. To utilize remote epitaxy as an ideal platform for growth and hetero-integration between various materials systems, the research team aims to study the mechanism of remote epitaxy at a fundamental level. By exploring the mechanism on various two-dimensional (2D) and three-dimensional (3D) materials, the research team expects to create a wider range of materials systems available for remote epitaxy. Also, being able to combine different materials systems together can benefit the physical sciences by discovering new functionalities, bringing advancements in engineering sciences and industry by improving current device fabrication techniques and their performances. PART 2: TECHNICAL DESCRIPTIONThe research team plans to focus on answering three major questions to understand remote epitaxy further: (1) the nature of the adatoms interaction with the underlying 2D/3D substrates, (2) the impacts of 2D materials and interfaces on remote epitaxy, and (3) the dynamic processes involved in adatom/nuclei migration and defect formation on 2D surfaces. To answer these questions, the research team will first reveal whether the remote epitaxy truly occurs in a ‘remote’ sense, which is the most fundamental conundrum that precedes any other questions. This has been difficult to answer because one can easily observe only the results of epitaxy, not the nucleation of adatoms. This issue is tackled by intentionally patterning the 2D layer and employing various materials with different growth properties as the epilayers. Second, impact of 2D layers is explored by studying how the type, crystallinity, and thickness of 2D interlayers alter the remote interaction of adatoms and substrates. In order to show the intrinsic role of 2D layers, direct growth of 2D layers is attempted on various substrates having different ionicity. Third, thermodynamics and kinetics of adatoms, their mergence to form nuclei, and nucleus-nucleus interaction on 2D layers are studied by understanding the nucleation mechanism, performing defect analysis, and exfoliating epilayers. Based on these results, the research team plans to demonstrate high-quality ultrathin films grown by remote epitaxy on directly-grown 2D layers with engineered nucleation conditions. As remote epitaxy allows mixed dimensional heterostructures, further study is done on 3D/various 2D/3D sandwiched structures to investigate new physical couplings between electronic states and magnetic properties. To the scientific community, these results are expected to utilize remote epitaxy for studying multifunctional and coupled material platforms that were not achievable by conventional methods.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.

第1部分：与发现新材料平台（例如碳纳米管或合成聚合物）一起开发的非技术描述科学和技术。该研究团队没有追逐全新的材料，而是针对一种新颖的转折，使现有的材料变得更平坦，更薄且更轻。早在2017年，这位主要研究人员发明了远程外观，这允许在石墨烯涂层模板上生长纳米级材料，之后被去除。这些薄薄的独立材料可以成为具有前所未有的性能的轻质，灵活设备的基础。到目前为止，对远程外观的研究主要限于对通常用于半导体的材料（例如硝酸盐和砷耐加仑）的经验观察。为了利用远程外观作为各种材料系统之间增长和异质整合的理想平台，研究小组旨在研究基本层面的远程外交机制。通过探索各种二维（2D）和三维（3D）材料的机制，研究小组希望创建更广泛的材料系统，可用于远程外观。此外，能够将不同的材料系统组合在一起可以通过发现新功能，通过改善当前的设备制造技术及其性能来带来工程科学和行业的进步，从而使物理科学受益。 PART 2: TECHNICAL DESCRIPTIONThe research team plans to focus on answering three major questions to understand remote epitaxy further: (1) the nature of the adapters interaction with the underlying 2D/3D substrates, (2) the impacts of 2D materials and interfaces on remote epitaxy, and (3) the dynamic processes involved in adatom/nuclei migration and defect formation on 2D surfaces.为了回答这些问题，研究团队将首先揭示远程外观是否真正出现在“远程”意义上，这是在其他任何问题之前最基本的难题。这很难回答，因为一个人只能很容易地观察外交的结果，而不是Adaptos的成核。通过故意对2D层进行图案并采用具有不同生长特性的各种材料来解决此问题。其次，通过研究2D中间层的类型，结晶度和厚度如何改变适应性和底物的远程相互作用来探索2D层的影响。为了显示2D层的固有作用，试图在具有不同离子性的各种底物上直接生长2D层。第三，通过理解成核机制，进行缺陷分析和去角质发作，研究了适应性的热力学和动力学，它们与核形成核的合并和核核的相互作用。基于这些结果，研究团队计划展示由远程外观在具有工程成核条件的直接生长的2D层上生长的高质量超薄膜。由于远程外观允许混合尺寸异质结构，因此对3D/各种2D/3D夹层结构进行了进一步的研究，以研究电子状态和磁性性能之间的新物理耦合。对于科学界来说，预计这些结果将利用远程发作来研究通过常规方法无法实现的多功能和耦合材料平台。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响标准通过评估来获得的支持。