CAREER: Revealing the Fundamental Mechanisms Behind the Dislocation-Induced Electronic States in III-V Semiconductors

职业：揭示 III-V 族半导体中位错诱发电子态背后的基本机制

• 批准号: 2047308
• 负责人: Tyler Grassman
• 金额: $ 61.4万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2047308&HistoricalAwards=false
• 关键词: CAREER; Revealing; Fundamental; Mechanisms; Behind

Nontechnical AbstractIn nearly any material, from the steel in bridge girders to the silicon in computer chips, it is the imperfections, or defects, that dictate critical aspects of its properties; sometimes these defects are intentional and helpful, sometimes they are unintended and harmful. Similarly, for nearly every type of defect, the specific reason for these effects can be traced down to a basic set of questions: What atomic species are involved? And how are they bonded to each other? If one can answer these questions, then one can better figure out how to either harness or mitigate defects. In the world of electronics, the growing need for new materials and technologies with higher performance, broader range of useful functions, and better reliability often drives scientists and engineers away from the limited palette of traditional materials and towards various combinations of different materials, which frequently possess fundamental dissimilarities. However, this approach can lead to the formation of detrimental defects. For the kinds of semiconductors that are used to create many vital technologies, including LEDs, lasers, solar cells, infrared sensors, high-power/speed transistors, and more, the atomic-scale nature of many defects remain a mystery. Therefore, this project seeks to identify the atomic structures of important defects and understand how they degrade the parent materials’ electronic and optical properties. Knowing this, researchers can figure out how to get around the challenges caused by defects, and perhaps even find new, beneficial uses for them. To further broaden the overall impact of this project, the principal investigator is working to combine this new science with existing knowledge to develop fresh and exciting course curricula, while the entire research team will share their expertise by creating highly accessible experimental methods training videos. Furthermore, the team is engaging with the local community through inclusive outreach events to help participants, children and adults alike, discover the connections between fundamental semiconductor materials properties, like those under investigation in this project, and the operation of the vast range of devices that they use throughout their day-to-day lives, igniting and encouraging the imaginations and interests of the new generations of diverse individuals that will not only contribute to fields of science and engineering, but will serve as positive influences to society.Technical AbstractDislocations within III-V semiconductors commonly arise as a result of dissimilar (e.g. lattice/symmetry mismatched) materials integration, and lead to detrimental sub-bandgap electronic defect levels that severely limit the usefulness of such materials systems. However, the fundamental, atomic-scale structure of III-V dislocations (especially the core), and thus the specific source of said defect levels, largely remains a mystery. The goal of this project is to fill this critical knowledge gap by testing the hypothesis that the characteristic defect levels resident at III-V dislocations can be directly attributed to specific, atomic-scale structural features. Employing a novel, correlative characterization framework of optoelectronic and structural spectroscopies and microscopies, with resolutions spanning from the macroscale to the atomic, the researchers are identifying the specific elemental species and bonding configurations that result in detrimental electronic defect levels. By combining this analysis with well-controlled sample epitaxy, they will further determine how these defect structures, and their associated properties, are impacted by the alloy composition, bandgap, and doping of the host material. Ultimately, this research is helping to build and support a true bottom-up compound semiconductor materials and process design approach, with defect mitigation as an achievable target, that is particularly valuable in applications where dissimilar integration is needed.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.

非技术摘要几乎所有材料，从桥梁的钢到计算机芯片中的硅，是不完美的或缺陷，决定了其性质的关键方面。有时这些缺陷是故意的和有用的，有时它们是意想不到的和有害的。同样，对于几乎每种类型的缺陷，这些效果的具体原因可以追溯到一组基本问题：涉及哪些原子物种？他们如何彼此联系？如果可以回答这些问题，那么人们就可以更好地弄清楚如何利用或减轻缺陷。在电子产品的世界中，对具有更高性能，更广泛的有用功能以及更高可靠性的新材料和技术的需求日益增长，通常会使科学家和工程师远离有限的传统材料调色板，并偏向不同材料的各种组合，这些材料经常具有基本的差异。但是，这种方法可能导致有害缺陷的形成。对于用于创建许多重要技术的半导体，包括LED，激光器，太阳能电池，红外传感器，高功率/速度晶体管等，许多缺陷的原子级本质仍然是一个谜。因此，该项目旨在识别重要缺陷的原子结构，并了解它们如何降低父​​材料的电子和光学特性。知道这一点，研究人员可以弄清楚如何解决缺陷造成的挑战，甚至可能为他们找到新的有益用途。为了进一步扩大该项目的整体影响，首席研究人员正在努力将这项新科学与现有知识相结合，以开发新鲜而激动人心的课程课程，而整个研究团队将通过创建高度可访问的实验方法培训视频来分享他们的专业知识。此外，团队正在通过包容性的外展活动与当地社区互动，以帮助参与者，儿童和成人，发现基本的半导体材料属性（例如该项目投资的基本半导体材料）之间的联系，以及他们在日常生活中使用的各种各样的运作，但不仅会为各种各样的生命而努力，而且在各种各样的生命中使用了各种各样的生命，而不是为各种各样的领域而付出了多样的兴趣，并为各种各样的兴趣提供了各种各样的想象力和兴趣，以至于各种各样的兴趣和兴趣的想象力，这些都不是在各种各样的生命中的想象力，而不是为各种各样的想象力而付出的想象力III-V半导体内部的技术抽象定位通常是由于异种（例如晶格/对称性不匹配）材料整合而产生的，并导致有害的亚键型电子缺陷水平严重限制了此类材料系统的有用性。但是，III-V位错（尤其是核心）的基本原子级结构，因此，所述缺陷水平的特定来源在很大程度上仍然是一个谜。该项目的目的是通过检验以下假设来填补这一关键知识差距，即III-V位错的特征缺陷水平可以直接归因于特定的原子级结构特征。研究人员采用光电子和结构光谱和显微镜的新型相关性特征框架，从宏观到原子学的分辨率，研究人员正在识别特定的元素物种和键合构型，从而导致有害的电子缺陷水平。通过将这种分析与良好控制的样品外观相结合，它们将进一步确定这些缺陷结构及其相关特性如何受到宿主材料的合金组成，带隙和掺杂的影响。最终，这项研究有助于建立和支持真正的自下而上的复合半导体材料和过程设计方法，并以缺陷作为可实现的目标，这在需要不同的整合的应用中尤其有价值。该奖项反映了NSF的法定任务，并通过使用基金会的知识优点和广泛影响来评估来表现出珍贵的支持，并通过评估获得了珍贵的支持。