CAREER: Van der Waals Epitaxial Heterostructures: Beyond 2D Materials

技术：本CAREER项目是研究具有可控能带结构的大面积、均匀、高质量二维范德华外延异质结构的合成。二维异质结构由不同过渡金属二硫化物材料（TMDC）的多层单层外延堆叠在一起组成。与其他合成二维TMDC材料的方法不同，该项目探索了首席研究员开发的一种独特的、自我限制的化学气相沉积工艺。该项目涉及在开发二维TMDC异质结构的可控可扩展合成以及理解异质结构的物理特征与能带结构之间的相关性方面的协同努力。它从研究自我限制生长机制的基本原理开始，然后是基于基本理解的可控可扩展合成技术的发展。它还涉及基于拉曼的表征计量工具的开发，为异质结构的组成和结构提供高通量表征。此外，首席研究员计划研究带结构与异质结构物理特征之间的相关性。非技术：该项目解决了材料科学新兴前沿领域的基本挑战。该项目的成功可以为合理设计一类具有原子尺度调谐成分和结构的新型人工材料提供能力。它为首席研究员追求其职业目标奠定了基础，该目标旨在研究二维异质结构的新物理现象，并探索这些材料在光电子领域的应用。新材料平台可以为包括信息技术、太阳能收集、发光二极管和柔性电子/光子器件在内的广泛领域开辟未开发的机会。该项目的研究部分被整合到多方面的教育和推广活动中，旨在激励学生（高中、本科生和研究生）在STEM学科中追求职业，并旨在加强中学和大学材料科学课程。除了为本科生和研究生提供研究培训外，该教育计划还包括指导高中生参加大学前的科学竞赛，并在高中的AP化学课上担任客座讲师。

Technical: This CAREER project is to study the synthesis of large-area, uniform, and high-quality two-dimensional (2D) van der Waals epitaxial heterostructures with controlled band structures. The 2D heterostructure consists of multiple monolayers of dissimilar transition metal dichalcogenide materials (TMDC) epitaxially stacked together. Unlike other approaches for the synthesis of 2D TMDC materials, this project explores a unique, self-limiting chemical vapor deposition process that the principal investigator has developed. The project involves synergistic efforts in the development of controlled scalable synthesis of 2D TMDC heterostructures and in the understanding of correlation between the physical features and band structures of the heterostructures. It starts with studies of the fundamentals of the self-limiting growth mechanism, followed by the development of techniques for the controlled scalable synthesis based on the fundamental understanding. It also involves the development of a Raman-based characterization metrology tool to provide high-throughput characterizations for the compositions and structures of the heterostructures. Additionally, the principal investigator plans to examine the correlation between the band structures and physical features of the heterostructures. Non-technical: This project addresses fundamental challenges in an emerging cutting-edge area of materials science. The success of this project can provide capabilities to rationally design a new class of artificial materials with compositions and structures tuned at the atomic scale. It lays down the groundwork for the principal investigator to pursue his career goal that aims to investigate new physical phenomena of 2D heterostructures and to explore these materials for applications in the field of optoelectronics. The new material platform can open up unexplored opportunities for a wide range of fields including information technology, solar energy harvesting, light emission diodes, and flexible electronic/photonic devices. The research component of this project is integrated into multifaceted educational and outreach activities that aim to inspire students (high school, undergraduate, and graduate) to pursue careers in the STEM disciplines and aim to enhance the secondary school and university curricula in materials science. In addition to providing research training for students at both undergraduate and graduate levels, the education plan includes mentoring high-school students to participate in pre-college scientific competitions and guest lectures in high schools' AP chemistry classes.