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.

在几乎所有材料中，从桥梁中的钢到计算机芯片中的硅，都是不完美或缺陷决定了其性能的关键方面;有时这些缺陷是故意的和有益的，有时它们是无意的和有害的。类似地，对于几乎每一种类型的缺陷，这些影响的具体原因可以追溯到一组基本问题：涉及哪些原子种类？他们是如何互相联系的呢？如果你能回答这些问题，那么你就能更好地找出如何利用或减轻缺陷。在电子世界中，对具有更高性能、更广泛的有用功能和更好可靠性的新材料和技术的需求不断增长，这往往促使科学家和工程师远离传统材料的有限调色板，转向不同材料的各种组合，这些材料通常具有根本的差异。然而，这种方法可能导致有害缺陷的形成。对于用于创造许多关键技术的半导体类型，包括LED，激光器，太阳能电池，红外传感器，高功率/高速晶体管等，许多缺陷的原子尺度性质仍然是一个谜。因此，该项目旨在确定重要缺陷的原子结构，并了解它们如何降低母体材料的电子和光学特性。知道了这一点，研究人员就可以找出如何解决缺陷带来的挑战，甚至可能找到新的、有益的用途。为了进一步扩大该项目的整体影响，首席研究员正在努力将这一新科学与现有知识相结合，以开发新的和令人兴奋的课程，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，该团队正在通过包容性的外展活动与当地社区接触，以帮助参与者，儿童和成人，发现基本半导体材料特性之间的联系，如本项目中正在调查的那些，以及他们在日常生活中使用的各种设备的操作。点燃和鼓励新一代不同个体的想象力和兴趣，这不仅有助于科学和工程领域，技术摘要III-V族半导体中的位错通常是由于不同的这会导致（例如，晶格/对称性失配的）材料集成，并且导致严重限制这种材料系统的有用性的有害的子带隙电子缺陷水平。然而，III-V位错（特别是核心）的基本原子尺度结构，以及所述缺陷能级的具体来源，在很大程度上仍然是一个谜。该项目的目标是通过测试以下假设来填补这一关键的知识空白：III-V位错中的特征缺陷水平可以直接归因于特定的原子级结构特征。采用光电和结构光谱学和显微镜的新型相关表征框架，分辨率从宏观尺度到原子尺度，研究人员正在确定导致有害电子缺陷水平的特定元素种类和键合构型。通过将这种分析与良好控制的样品外延相结合，他们将进一步确定这些缺陷结构及其相关特性如何受到合金成分、带隙和主体材料掺杂的影响。最终，这项研究有助于建立和支持一个真正的自下而上的化合物半导体材料和工艺设计方法，并将缺陷缓解作为一个可实现的目标，这在需要不同集成的应用中特别有价值。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。