Time-Resolved EELS of Photonic Crystals and Glasses

光子晶体和玻璃的时间分辨 EELS

• 批准号: 0603993
• 负责人: Nan Jiang
• 金额: $ 52.07万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0603993&HistoricalAwards=false
• 关键词: Time; Resolved; EELS; Photonic; Crystals

NON-TECHNICAL DESCRIPTION: Glasses consisting primarily of Ge, As, S, Se and Te (chalcogenides) constitute an important class of optical materials that can potentially enable a wide range of modern technologies including photonics, telecommunication, sensors and memory devices. However, successful compositional design of chalcogenides with optimized properties tailored for these technological applications needs formulation of accurate predictive models, which in turn requires fundamental data on the atomic structure and dynamics of these materials. This research program aims to use state-of-the-art experimental and simulation methods to study the atomic structure and to investigate dynamical phenomena in these glasses and in the liquids from which they derive. These results will be used to formulate and test models linking the microscopic structure and dynamics with the macroscopic properties, which will play key role in smart compositional engineering of these materials. Students in this research program will learn to investigate problems in the realm of "basic science" that underlies industrial applications. The use of experimental facilities at the Argonne National Laboratory (ANL) will enrich the graduate education and training experience through participation in a unique research environment and will foster intellectual exchange. This program will coordinate with the underrepresented minority-serving and K-12 outreach programs on campus to attract and recruit underrepresented graduate students and to increase the awareness of students in the science and technology of glassy materials. TECHNICAL DETAILS: This program seeks to study the structure-property relationships and to develop an atomic scale understanding of the structural mechanisms of transport and relaxation near the glass transition (Tg) in complex chalcogenide glasses in the Ge-As-S-Se-Te system. A combination of neutron/x-ray diffraction and Reverse Monte Carlo modeling will be used to obtain an unusually complete picture of the intermediate-range atomic structures of these materials for the first time. The temperature induced structural changes and the dynamics of exchange among structural species in these glasses and parent liquids will be characterized in situ with 77Se and 125Te nuclear magnetic resonance (NMR) spectroscopy at temperatures near and above Tg, and ex situ, on samples with different time-temperature histories by a combination of NMR and Raman spectroscopic techniques. These results will be used to develop predictive models, linking the atomic structure and dynamics with macroscopic physical properties, which are crucial for compositional optimization of these materials for a wide range of technological applications. This work includes significant training of graduate students in state-of-the-art spectroscopic, diffraction and simulation techniques.

非技术描述：主要由 Ge、As、S、Se 和 Te（硫属化物）组成的玻璃构成了一类重要的光学材料，可以实现包括光子学、电信、传感器和存储设备在内的各种现代技术。然而，要成功地设计具有针对这些技术应用而定制的优化性能的硫族化物，需要制定准确的预测模型，而这反过来又需要有关这些材料的原子结构和动力学的基础数据。 该研究计划旨在使用最先进的实验和模拟方法来研究原子结构并研究这些玻璃及其衍生液体中的动力学现象。这些结果将用于制定和测试将微观结构和动力学与宏观特性联系起来的模型，这将在这些材料的智能组成工程中发挥关键作用。 该研究项目的学生将学习调查工业应用基础的“基础科学”领域的问题。 使用阿贡国家实验室 (ANL) 的实验设施将通过参与独特的研究环境来丰富研究生教育和培训经验，并促进知识交流。该计划将与校园内代表性不足的少数族裔服务和 K-12 外展计划相协调，以吸引和招收代表性不足的研究生，并提高学生对玻璃材料科学技术的认识。 技术细节：该项目旨在研究结构-性能关系，并在原子尺度上理解 Ge-As-S-Se-Te 中复杂硫属化物玻璃中玻璃化转变 (Tg) 附近的输运和弛豫结构机制系统。 中子/X射线衍射和逆蒙特卡罗建模的结合将用于首次获得这些材料的中程原子结构的异常完整的图像。 这些玻璃和母液中的温度引起的结构变化和结构物种之间的交换动态将在接近和高于 Tg 的温度下使用 77Se 和 125Te 核磁共振 (NMR) 光谱进行原位表征，以及在不同温度下的样品上进行非原位表征。结合核磁共振和拉曼光谱技术的时间-温度历史。 这些结果将用于开发预测模型，将原子结构和动力学与宏观物理性质联系起来，这对于这些材料的成分优化以实现广泛的技术应用至关重要。这项工作包括对研究生进行最先进的光谱、衍射和模拟技术方面的重要培训。