NMR Studies of Optically Active Impurities under In Situ Illumination

这是对俄勒冈州立大学一位高级教授的续展奖项，该项目将利用核磁共振的局部化学特性来研究半导体和绝缘体中光学活性杂质的微观特性。固体核磁共振技术将与原位照明相结合，以研究光激发对电子结构和与特定杂质相关的局部原子排列的影响。将特别注意双稳态杂质，如镉镉中的镓或铟和其他II-VI化合物以及CdF2。光学增强的主体(~(113)Cd、~(125)Te和~(19)F)核的自旋晶格驰豫将被用作双稳杂质向常规有效质量施主转变的指示器。杂质物种核磁共振，特别是69Ga，将与原位照明相结合，寻找杂质基态结构重排的直接证据。杂质物种核磁共振(69Ga和63Cu)也将用于研究SrS(Cu，M)和ZnS(Mn，Ga)等荧光粉中活性中心的局域环境。我们的目标是阐明对这些杂质的微观理解，这将有助于为特定的电子和光学应用而设计这类材料。拟议的实验将为博士和硕士研究生教育和本科生研究机会提供场所；它们还将被用于以项目和演示的形式丰富现代物理和固体物理的本科生课程。%特定杂质的受控引入对于确定具有重要技术意义的电子和光学材料的性能至关重要。俄勒冈州立大学高级教授的这一续展奖项是为了表彰将专注于一类光学活性杂质的研究。这种杂质在发光时会改变其原子尺度的性质，或者在主体材料中受到照明或电流的影响时会发光。这些材料的应用包括用于平板显示器的发光元件和光学数据存储。核磁共振(核磁共振)是一种揭示材料中特定化学元素环境的原子尺度细节的光谱学。在这项研究中，核磁共振将被用来探测光照对宿主原子环境的影响，例如Cd在CdTe或CdF2中，或者在这些材料和正在开发的平板显示器用荧光粉中的杂质，如Ga。这项研究和相关研究的目标是达到微观理解的水平，这将促进这类材料的工程应用于特定的电子和光学应用。拟议的研究将纳入本科生和研究生教育。博士和论文研究将为进入美国高科技行业培养毕业生。本科生将参与俄勒冈州立大学的本科研究，并通过丰富(项目和演示)现代物理和固体物理的正式课程。*

This is a renewal award to a senior professor at Oregon State University for a project that will exploit the local, chemically specific properties of nuclear magnetic resonance (NMR) to investigate the microscopic properties of optically active impurities in semiconductors and insulators. Solid-state NMR techniques will be combined with in situ illumination to examine the effects of optical excitation on the electronic structure and local atomic arrangements associated with specific impurities. Particular attention will be given to bistable impurities such as Ga or In in CdTe and other II-VI compounds as well as CdF2. Optically enhanced host (113Cd, 125Te, and 19F) nuclear spin-lattice relaxation will be used as an indicator of conversion of the bistable impurities to conventional effective mass donors. Impurity species NMR, especially 69Ga, will be used in combination with in situ illumination to search for direct evidence of structural rearrangements in the impurity ground state. Impurity species NMR (69Ga and 63Cu) will also be used to study the local environments of active centers in phosphors such as SrS(Cu,M) and ZnS(Mn, Ga). The goal is to elucidate a microscopic understanding of these impurities that will facilitate the engineering of this class of material for specific electronic and optical applications. The proposed experiments will provide a venue for Ph.D. and M.S. graduate education and undergraduate research opportunities; they will also be exploited for enrichment of undergraduate courses in Modern Physics and Solid State Physics in the form of projects and demonstrations.%%%The controlled introduction of specific impurities is critical in determining the properties of technologically important electronic and optical materials. This renewal award to a senior professor at Oregon State University is for research that will focus on a class of impurities that are optically-active. Such impurities change their atomic-scale properties when illuminated or emit light when subject to illumination or electric currents in the host material. The applications of these materials include light emitting elements for flat panel displays and optical data storage. Nuclear magnetic resonance (NMR) is a spectroscopy that reveals atomic-scale details of the environments of specific chemical elements in a material. In this research, NMR will be used to probe the effects of illumination on host atom environments, say Cd in CdTe or CdF2, or impurities such as Ga in these materials and in phosphors being developed for flat panel displays. The goal of this and related research is to reach a level of microscopic understanding that will facilitate the engineering of this class of material for specific electronic and optical applications. The proposed research will be integrated into undergraduate and graduate education. Ph.D. and thesis research will train graduates for entry into U.S. high technology industry. Undergraduates will participate in undergraduate research and through enrichment (projects and demonstrations) of formal courses in Modern Physics and Solid State Physics at Oregon State University.***