CAREER: Atomic scale understanding of the doping incorporation and transport properties in ultrawide band gap semiconductors

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公共法律117-2)。非技术描述：在包括家用电器、全电动和混合动力汽车在内的广泛应用中提高电力转换效率，以及在具有成本效益的可再生能源中提取和转换可以节省能源，显著降低成本，从而使经济和环境受益。超宽带隙半导体是电力电子元件革命性的潜在材料体系，是一类具有大带隙能量的半导体。提高它们的性能依赖于对有效产生和控制载流子的机制以及这些载流子在材料中如何相互作用的关键了解。这个项目揭示和描述了这些材料系统中电荷载流子和微结构的“真实情况”，包括掺杂剂与缺陷的相互作用，以及这些原子尺度的特征如何影响电功能。这项工作是通过一种创新的方法实现的，该方法将三维原子尺度成像工具、原子探测器断层成像与原子尺度数据的统计和计算建模相结合，建立了与电导率的直接联系，否则将难以识别和缓解。首席研究员努力激励本科生和研究生，特别是女性和代表性不足的少数民族，通过让他们接触到先进材料的令人兴奋的发展来解决重要的社会问题，从而在材料科学和工程领域追求职业生涯。首席调查员还将通过组织夏季讲习班和专题讨论会，提高对先进材料表征的认识，为材料设计和开发产生智能数据。课程将强调多学科方法来教授工程概念，并将它们与现实世界的应用相结合，以解决社会进步的挑战。技术描述：本研究项目将提供对超宽带隙半导体中电传输特性的基本了解，以促进高功率电子和清洁能源技术的发展。超宽带隙半导体技术由于缺乏对掺杂电学功能的了解，以及对有助于电荷补偿的原子尺度特征的识别和检测的缺乏而受到阻碍。利用原子探针层析成像技术，结合机器学习和显微数据的统计建模，将开发一种新的框架来检测和量化掺杂的溶解度、掺杂扩散、杂质、空位和缺陷复合体。首要目标是产生有关微结构对电子传输影响的专门知识，超越现有技术的限制。这项研究致力于通过以下方式改变掺杂工程和电导优化：i)开发能够表征掺杂和掺杂-缺陷相互作用的新方法，从而以前所未有的分辨率和精度进行电荷补偿；ii)对原子到纳米级的结构和缺陷如何影响电子传输有新的见解；iii)验证现有的电荷补偿理论，为进一步发展材料结构化学、电力电子和清洁能源生产提供重要投入；以及iv)获得关于材料结构和化学的新知识，以帮助原理和设计标准在超宽带隙半导体及其他领域获得优异的材料性能。紧密结合的研究和教育部分为本科生和研究生提供了关于高级显微镜、机器学习建模和超宽带隙半导体的跨学科培训机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Nontechnical Description: Improving power conversion efficiency in a wide range of applications including consumer appliances, all-electric and hybrid-electric vehicles, and extraction and conversion in cost-effective renewable energy sources can save energy, significantly reducing costs, benefiting both the economy and environment. The potential material system for revolutionizing power electronics components is ultra-wide bandgap semiconductors, a class of semiconductors with large bandgap energy. Enhancing their performance relies on critical understanding of mechanisms to efficiently generate and control charge carriers and how these carriers interact within the materials. This project reveals and describes “what really happens” at the scale of charge carriers and microstructures within these material systems, including the dopant-defect interaction and how these atomic scale features affect the electrical functionalities. This work is made possible by an innovative approach that integrates a three-dimensional atomic scale imaging tool, atom probe tomography with statistical and computational modeling on the atomic scale data, establishing a direct link with the electrical conductivity that would be difficult to identify and mitigate otherwise. The principal investigator strives to inspire students at undergraduate and graduate levels, especially women and underrepresented minorities, to pursue a career in materials science and engineering by exposing them to the exciting development of advanced materials to solve important societal problems. The principal investigator will also increase awareness of advanced material characterization to generate smart data for material design and development by organizing summer workshops and symposium. Coursework will emphasize multidisciplinary approaches to teach engineering concepts and connect them with real-world applications to solve challenges for the advancement of society.Technical description: This research project will provide a fundamental understanding of electrical transport properties in ultra-wide band gap semiconductors to advance high power electronics and clean energy technologies. Ultra-wide bandgap semiconductor technology is hindered by the lack of knowledge of the dopant incorporation on electrical functionalities and identification and detection of atomic scale features contributing to charge compensation. A novel framework will be developed to detect and quantify dopant solubility, dopant diffusion, impurities, vacancies, and defect complexes by leveraging atom probe tomography coupled with machine learning and statistical modeling on microscopy data. The overarching goal is to generate know-how on the impact of microstructures on electrical transport, beyond the limits of existing techniques. This research aspires to transform the doping engineering and electrical conductivity optimization by: i) developing novel methodologies that can characterize dopant incorporation and dopant-defect interaction that leads to charge compensation with unprecedented resolution and precision; ii) gaining new insight into how atomic to nanoscale structures and defects impacts the electrical transport; iii) validating existing theories on charge compensation and providing important inputs for further developing material structure-chemistry for power electronics and clean energy generation, and iv) acquiring new knowledge on material structure and chemistry to aid the principles and design criteria to achieve outstanding material performance in ultra-wide bandgap semiconductors and beyond. The closely integrated research and education components provide interdisciplinary training opportunities for undergraduate and graduate students on advanced microscopy, machine learning modeling, and ultra-wide bandgap semiconductors.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.