CAREER: Point Defects in Two-dimensional Material Systems: Fundamentals and New Perspectives

职业：二维材料系统中的点缺陷：基础知识和新视角

• 批准号: 1552220
• 负责人: Sefaattin Tongay
• 金额: $ 50万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1552220&HistoricalAwards=false
• 关键词: CAREER; Point; Defects; Two; dimensional

Nontechnical Description: It is known that introducing defects or imperfections into a crystalline material, either by removing atoms or adding foreign atoms, can change material's properties, and this approach has led to many ground breaking applications such as light emitting diodes, transistors and sensors. Today, there is a good understanding of how to manipulate these imperfections to achieve the desired properties of traditional semiconductors such as silicon. However, researchers are just starting to understand how to use defects to manipulate a whole new class of materials: two-dimensional (2D) semiconductors that are atomically thin, which have an unusual set of properties and are expected to perform far better than traditional semiconductors in some regards. The research component of this CAREER award is to explore innovative ways to introduce defects in 2D materials and to study how defects change the 2D material's properties. One way this can be done is to remove atoms by striking the material with energetic particles. Alternatively, foreign atoms with different electrical charges can be anchored in their place. The research team uses state-of-the-art techniques to visualize how these imperfections form, how they react and how they impact the material properties. This project also brings nanoscience and 2D material concepts to the public through open house events and summer camps for high-school students, as well as participation of graduate and undergraduate students in active research. Findings from this project are disseminated through journal publications, conference presentations, and a publicly-accessible 2D materials database, which the team is developing in collaboration with a non-profit organization, MaterialsProject.org.Technical Description: This research project aims to uncover the physics of point defects, in particular those in emerging 2D semiconducting materials such as WS2, GeSe, GaSe, and InTe. The research team uses advanced high-resolution spectroscopy and microscopy techniques to investigate chalcogen vacancies, anti-site defects, and substitutionals. Defects are introduced at desired defect concentrations during growth or after growth by alpha-particle irradiation to achieve desired material properties. Nano-photoluminescence, ultra-fast spectroscopy, and electron energy loss spectroscopy measurements allow determination of energy states of defects and effects of defects on the excitonic complexes, optical absorption and emission characteristics, as well as electronic structure of 2D materials. Transmission electron microscopy (TEM) studies help to determine structural characteristics, relaxation dynamics, and diffusion speed of defects. The overarching goal is to measure, analyze, and establish the roles of point defects in determining the optical and electronic properties of select 2D semiconducting materials and explore new routes to control material properties on demand.

非技术描述：众所周知，通过去除原子或添加外源原子来将缺陷或瑕疵引入结晶材料，可以改变材料的特性，并且这种方法导致了许多破碎的应用，例如光发射二极管，晶体管和传感器。如今，人们对如何操纵这些缺陷以达到传统半导体（如硅）的期望特性有很好的了解。但是，研究人员刚刚开始了解如何使用缺陷来操纵全新的材料：二维（2D）的半导体，它们具有原子上很薄的材料，它们具有一系列不同寻常的特性，并且预计会比传统的半导体更好在某些方面。该职业奖的研究组成部分是探索创新的方式来引入2D材料中的缺陷，并研究缺陷如何改变2D材料的特性。这可以做到的一种方法是通过用能量颗粒击中材料来去除原子。或者，可以将带有不同电荷的外国原子锚定在其位置。研究团队使用最先进的技术来形象化这些缺陷的形成，它们的反应方式以及如何影响材料特性。该项目还通过开放式活动和夏令营为高中生带来了纳米科学和2D材料概念，以及研究生和本科生的积极研究。该项目的发现是通过期刊出版物，会议演示文稿和公开访问的2D材料数据库传播的，该团队正在与非营利组织Mettersproject.org.org.org.org.technical描述：该研究项目旨在揭露该研究项目：旨在揭露该研究项目点缺陷的物理学，尤其是在新出现的2D半导体材料（例如WS2，GESE，GASE和INTE）中的物理学。研究小组使用先进的高分辨率光谱和显微镜技术来研究chalcogen空位，抗位点缺陷和替代物。在生长期间或通过α粒子辐射生长后，以所需的缺陷浓度引入缺陷，以实现所需的材料特性。纳米 - 光致发光，超快速光谱和电子能量损失光谱测量值可以确定缺陷的能量状态以及缺陷对激发复合物的影响，光学吸收和发射特性以及2D材料的电子结构。透射电子显微镜（TEM）研究有助于确定缺陷的结构特征，松弛动力学和扩散速度。总体目标是测量，分析和确定点缺陷在确定选定2D半导体材料的光学和电子特性中的作用，并探索按需控制材料特性的新途径。