Large-Area Synthesis and Carrier Transport and Dynamical Properties of Atomically Thin Two-Dimensional In2Se3

非技术描述：固体材料中的电子行为是材料电学和光学特性的核心，在决定电子和光电子器件（如晶体管、光电探测器和太阳能电池）的性能方面起着关键作用。近年来，厚度降至单原子层的二维材料已成为一类新型材料体系，具有超越传统块状材料的新特性。本项目研究了技术上重要的二维材料硒化铟的载流子输运和动力学，并对合成-结构-性质关系有了基本的了解。这项研究已纳入教育和外联活动。除了为本科生和研究生提供研究机会，包括那些来自科学和工程领域代表性不足的群体，该项目产生的研究成果被纳入课堂教学，并通过夏季研讨会为高中生提供光学，电路和光伏的实践经验。技术描述：本研究项目旨在建立二维硒化铟载流子输运和超快载流子动力学的基本认识。该项目涉及利用范德华外延在大面积上合成原子薄单晶硒化铟，并利用透射电子显微镜、共聚焦拉曼光谱、扫描探针显微镜和空间分辨超快光泵浦探针技术的组合进行性质表征。该项目解决了该材料中的重要问题，特别是多数载流子和少数载流子的输运性质和动力学，以及性质、结构和材料合成之间的相关性。对这种合成-结构-性能关系的理解为创新光电应用提供了基础材料科学基础。

Nontechnical Description: The behavior of electrons in a solid material is central to electrical and optical characteristics of the material and plays a critical role in determining the performance of electronic and optoelectronic devices such as transistors, photodetectors, and solar cells. Recently, two-dimensional materials, with the thickness down to a single atomic layer, have emerged as a new class of material systems with novel properties beyond conventional bulk materials. This project studies the charge carrier transport and dynamics in a technologically important two-dimensional material, indium selenide, and develops a fundamental understanding of the synthesis-structure-property relation. The research is integrated into education and outreach activities. In addition to providing research opportunities for undergraduate and graduate students, including those from the underrepresented groups in science and engineering, the research results generated in this project are incorporated into the classroom teaching and hands-on experience with optics, electric circuits, and photovoltaics is offered to high school students through a summer workshop.Technical Description: This research project aims to establish a fundamental understanding of charge carrier transport and ultrafast carrier dynamics in two-dimensional indium selenide. This project involves patterned synthesis of atomically thin single-crystal indium selenide over a large area using van der Waals epitaxy, and property characterizations utilizing a combination of transmission electron microscopy, confocal Raman spectroscopy, scanning probe microscopy, and spatially resolved ultrafast optical pump-probe techniques. This project addresses important issues in this material, particularly the transport properties and dynamics of both majority and minority charge carriers, and the correlation among the properties, structures, and material synthesis. The understanding of this synthesis-structure-property relation provides a fundamental materials science basis for innovative optoelectronic applications.