Exploiting Enhanced Polarization from Optically-Pumped NMR of Semiconductors

* 技术摘要 * 一种新型的光谱学结合了光泵电子与NMR检测，称为OPNMR，正在开发并应用于一系列重要类别的直接带隙III-V族半导体。OPNMR利用光学取向的电子，这些电子与周围的核自旋耦合;然后可以观察到增强的NMR信号。与光学相关缺陷相关的缺陷位点和掺杂剂将被光谱识别。极化转移计划，其中信号增强在一个区域通过核自旋扩散到其他地区旅行将被探索，开辟OPNMR的新应用的可能性。理论和实验工作将在这个项目中紧密结合，计算能带结构和自旋相关的光学跃迁，工业合作伙伴将协助选择异质结构器件进行分析。这项研究的附带好处将包括OPNMR现象的模型，这些方法将应用于II-VI族和IV族半导体。研究生将接受尖端光谱技术的教育和培训，这使他们能够在包括激光器，半导体器件，NMR/MRI光谱学在内的各个领域从事职业，并建立化学，物理和工程方面的知识和经验。与工业合作伙伴的工作经验将是非常宝贵的，以帮助学生做出明智的职业选择，并为未来的研究机会提供联系。非技术摘要 * 尖端的光谱工具正在开发中，它将联合收割机激光与核磁共振或NMR（一种与医学中使用的MRI密切相关的技术）结合起来，用于研究半导体。半导体材料具有巨大的经济和工业重要性，因为它们形成电子元件和设备的基本构建块。半导体是一种充当电子“管道”的材料，控制电子在材料内部流动的位置和方式，例如计算机芯片或数码相机中的像素。通过将激光照射到半导体上，产生电子。 了解这些光激发电子的行为对器件性能非常重要，激光+NMR技术用于通过它们与周围环境的相互作用来监测电子自旋。 在这个项目中，研究生将接受这些先进技术的教育和培训，使他们能够在各个领域从事职业（即，激光，半导体器件，核磁共振/核磁共振光谱学），它建立了化学，物理和工程方面的知识和经验。合作团队包括一个工业合作伙伴，从而为我们的学生提供真实世界的经验，并为该项目的高级（学术）人员提供更广泛的商业视角。

****Technical Abstract****A new type of spectroscopy combining optical-pumping of electrons with NMR detection, termed OPNMR, is being developed and applied to a series of important classes of direct-gap III-V semiconductors. OPNMR exploits the optically-oriented electrons, which couple to surrounding nuclear spins; enhanced NMR signals can then be observed. Defect sites and dopants related to optically-relevant defects will be spectroscopically identified. Polarization transfer schemes, whereby signal enhancements in one region travel via nuclear spin diffusion to other regions will be explored, opening up the possibility of new applications of OPNMR. Theory and experimental work will be closely coupled in this project with calculations of the bandstructure and spin-dependent optical transitions, and an industrial partner will assist in selection of heterostructure devices for analysis. Ancillary benefits of this research will include models of OPNMR phenomena for these methods to be applied to II-VI and Group IV semiconductors. Graduate students will be educated and trained in cutting-edge spectroscopy techniques, which enables them to pursue careers in a variety of areas including lasers, semiconductor devices, NMR/MRI spectroscopy, and it builds both knowledge and experience in chemistry, physics, and engineering. Experience working with an industrial partner will be invaluable to help students make informed career choices and to provide contacts for future research opportunities.****Non-technical Abstract****Cutting-edge spectroscopic tools are being developed that combine lasers with nuclear magnetic resonance, or NMR (a technique that is closely-related to MRI's used in medicine), to study semiconductors. Semiconductor materials are of enormous economic and industrial importance because these form the basic building blocks for electronic components and equipment. Semiconductors are a type of material that act as a "pipeline" for electrons, controlling where and how electrons flow inside the material, such as in computer chips or the pixels in digital cameras. By shining laser light onto the semiconductor, electrons are generated. Understanding how these photoexcited electrons behave is important to device performance, and the laser+NMR techniques are used to monitor the electron spins through their interactions with the surroundings. In this project, graduate students will be educated and trained in these advanced technologies, which enables them to pursue careers in a variety of areas (i.e., lasers, semiconductor devices, NMR/MRI spectroscopy), and it builds knowledge and experience in chemistry, physics, and engineering. The collaborative team includes an industrial partner thus offering real-world experience for our students, and a broader commercially-focused perspective to the senior (academic) personnel on this project.