FRG: Nanoscale Structural Order in Amorphous Materials and its Relation to Diffusion and Electronic Defects

FRG：非晶材料的纳米级结构秩序及其与扩散和电子缺陷的关系

• 批准号: 0605890
• 负责人: John Abelson
• 金额: $ 87.25万
• 依托单位: University of Illinois at Urbana-Champaign
• 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: 2006-08-15 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605890&HistoricalAwards=false
• 关键词: FRG; Nanoscale; Structural; Order; Amorphous

TECHNICAL: This research offers new insights into nanoscale atomic ordering, its connection to defects and defect clustering in amorphous materials, and the influence of nanoscale order and defects on properties. The project is a collaborative focused research project (FRG), and addresses: (1) nanoscale structure as a function of composition in chalcogenide glasses with the goal of building a detailed model of intermediate phases; (2) optically-driven, nanoscale structural transformations that cause photodarkening and photomelting in chalcogenide glasses; (3) influence of nanoscale order on thermal stability and phase transformations of amorphous transition metal diboride thin films; and (4) connection between impurity diffusion and nanoscale order in amorphous diborides, which may be mediated by a spatially non-uniform defect distribution caused by nanoscale order. The chalcogenides have important applications in photonics in addition to being prototypical glass-forming networks. Several glasses in the intermediate phase composition region exhibit extremely high Kerr optical non-linearities that are being investigated for all-optical switching. Photodarkening enables easy fabrication of waveguides and diffraction gratings. The metal diborides are candidate diffusion barriers for silicon microelectronic metallizations, for which low impurity diffusion and high thermal stability in extremely thin films are essential. Research on the four problems above will lay basic materials science groundwork for these applications. NONTECHNICAL: A primary impact of this research collaboration is establishment of a new paradigm for the structural analysis of amorphous materials, in which one uses scattering probes to characterize the structure and chemistry of a sample from nearest-neighbors to a few nanometers, then uses modeling techniques to synthesize an atomistic structural model consistent with what is known about the particular material. That model is then studied to further elucidate the structure and properties of the material. Key innovations are nanoscale structural information from fluctuation electron microscopy included in synthesis of experimental data and ab initio energetics with experimentally constrained molecular relaxation. The project will provide downloadable manuals, computer code and make use of technical meetings to disseminate these tools broadly in the scientific community, where they will eventually be used to address a wide range of materials science problems. The effort also provides an exceptional opportunity for the training of students and post-docs in a multidisciplinary, collaborative environment that is at the forefront of the integration of experimental and computational tools in materials. The project also includes activities designed to enhance participation of underrepresented groups in science and engineering.

技术：本研究为纳米级原子有序、其与非晶材料中缺陷和缺陷聚集的联系，以及纳米级有序和缺陷对性能的影响提供了新的见解。该项目是一个以合作为重点的研究项目（FRG），并解决：(1)纳米级结构作为硫系玻璃成分的函数，目标是建立中间相的详细模型；(2)光驱动的纳米级结构转变导致硫系玻璃的光变暗和光熔化；(3)纳米量级对非晶过渡金属二硼化物薄膜热稳定性和相变的影响；(4)非晶二硼化物中杂质扩散与纳米级有序之间的联系，这可能是由纳米级有序引起的空间不均匀缺陷分布所介导的。硫族化合物除了是玻璃形成网络的原型外，在光子学中也有重要的应用。在中间相位组成区域的几种玻璃表现出极高的克尔光学非线性，正在研究用于全光开关。光变暗使波导和衍射光栅的制造变得容易。金属二硼化物是硅微电子金属化的候选扩散屏障，在极薄的薄膜中，低杂质扩散和高热稳定性是必不可少的。对上述四个问题的研究将为这些应用奠定基础的材料科学基础。非技术：这项研究合作的主要影响是建立了非晶材料结构分析的新范例，其中使用散射探针表征样品的结构和化学性质，从最近的邻居到几纳米，然后使用建模技术合成与已知的特定材料相一致的原子结构模型。然后研究该模型以进一步阐明材料的结构和性能。关键的创新是包含在实验数据合成中的波动电子显微镜的纳米级结构信息和实验约束分子弛豫的从头算能量学。该项目将提供可下载的手册、计算机代码，并利用技术会议在科学界广泛传播这些工具，这些工具最终将用于解决广泛的材料科学问题。这一努力也为学生和博士后的培训提供了一个特殊的机会，在一个多学科的合作环境中，在材料实验和计算工具的整合方面处于最前沿。该项目还包括旨在加强代表性不足的群体参与科学和工程的活动。