Heterostructures and Superlattices of Two-Dimensional Layered Materials

非技术描述：二维层状材料代表了一类新的材料系统，用于在单原子厚度的极限下探索基础化学和物理，并有可能开辟现有材料无法企及的全新技术机会，如高速电子学、超柔性电子学、光电探测器、光伏和新型传感器。这个项目研究了二维材料的基本成核和生长机制，并开发了合成策略来生长这些原子薄的晶体，这些晶体在横向和垂直方向上都有明确的边界。这项研究与教育和外联活动密切结合在一起。该项目为学生提供超越传统教育界限的教育和培训机会，包括培养创业技能。研究中开发的材料和方法被整合到研究生和本科课程中，以拓宽PI实验室以外的教育经验。技术描述：该项目旨在设计和合成二维层状材料及其异质结构和超晶格，并精确控制材料参数，包括化学成分、物理尺寸、原子层数量和异质结构界面。该项目使用原位透射电子显微镜来研究成核和生长动力学，并发展了对原子层内和原子层之间的二维晶体生长的原子理解。该项目还开发了一种激光辅助化学气相沉积方法，用于化学前体的可编程切换，以实现具有原子尖锐界面的异质结构的受控生长。用透射电子显微镜和扫描隧道显微镜研究了产物的结构、化学和电子调制。此外，该项目还研究了所得材料的基本电学和光学性质，并探索了它们在新型电子和光电子器件中的应用。

Nontechnical Description: Two-dimensional layered materials represent a new class of material systems for exploring fundamental chemistry and physics at the limit of single-atom thickness, and have the potential to open up completely new technological opportunities beyond the reach of the existing materials, such as high-speed electronics, ultra-flexible electronics, photodetectors, photovoltaics and novel sensors. This project investigates the fundamental nucleation and growth mechanisms of two-dimensional materials and develops synthetic strategies for the growth of these atomically thin crystals with well-defined boundaries in both lateral and vertical directions. The research is closely integrated with education and outreach activities. The project provides students with educational and training opportunities beyond traditional educational boundaries including developing entrepreneurial skills. The materials and methodologies developed in the research are integrated into graduate and undergraduate courses to broaden the educational experience beyond the PI's laboratory.Technical Description: This project aims to design and synthesize two-dimensional layered materials, their heterostructures and superlattices with a precise control of material parameters including chemical composition, physical dimension, number of atomic layers, and heterostructure interfaces. The project uses in-situ transmission electron microscopy to investigate the nucleation and growth kinetics and develops an atomistic understanding of two-dimensional crystal growth within and between atomic layers. The project also develops a laser-assisted chemical vapor deposition approach for programmable switching of chemical precursors to enable the controlled growth of heterostructures with atomically sharp interfaces. The structural, chemical and electronic modulation of the resulting materials is studied using transmission electron microscopy and scanning tunneling microscopy. In addition, the project investigates the fundamental electronic and optical properties of the resulting materials, and explores their applications for novel electronic and optoelectronic devices.