In-situ X-ray Scattering Studies of Oxide Epitaxial Growth Kinetics and Dynamics

氧化物外延生长动力学和动力学的原位 X 射线散射研究

• 批准号: 2336506
• 负责人: Randall Headrick
• 金额: $ 73.54万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-01 至 2027-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2336506&HistoricalAwards=false
• 关键词: situ; ray; Scattering; Studies; Oxide

PART 1: NON-TECHNICAL SUMMARYX-rays are a powerful tool for exploring materials, capable of measuring atomic structures through diffraction owing to their short wavelength and their ability to penetrate materials without strong absorption. Synchrotrons, among X-ray sources, stand out as the brightest available to scientists. This project employs real-time X-ray scattering to investigate the structure and properties of metal oxides, known for their remarkable electrical and magnetic properties. The researchers aim to unveil the full potential of these materials by closely studying their growth processes, with a specific focus on thin films. Thin films could give rise to properties significantly different to those in the bulk parent compounds from which the films derive. By continuously capturing an evolving X-ray scattering pattern during growth, the team gains insights into the atomic structure of crystalline layers as they assemble from the vapor phase. This understanding is pivotal in creating innovative materials with enhanced or entirely new properties, including the ability to store an electrical charge via a shift in positive and negative ions in the crystal lattice (ferroelectric effect) or generate electrical voltage under deformation (piezoelectric effect). Such effects, along with other more exotic ones, can be tailored through the growth of artificially produced thin films, such as those with alternating layers of two different materials, each only a few atoms thick. The unique properties of metal oxides find applications in electronic memories, detectors, actuators, and energy harvesters. Beyond its scientific impact, the project plays a crucial role in education and diversity by offering hands-on training to graduate students and involving undergraduates in cutting-edge research. PART 2: TECHNICAL SUMMARY This project explores fundamental questions surrounding the influence of growth processes on the structure, interfaces, and functional properties of metal oxide thin films. Going beyond the conventional goal of achieving high-quality films, the focus is on uncovering unique growth modes and interfaces that could lead to properties significantly divergent from those observed in the bulk parent compounds. The project integrates complementary measurements of ferroelectric films to establish a feedback loop between synthesis, structural characterization, and resulting material properties, allowing for comparisons with baseline properties of conventional materials. The research plan includes three key pursuits: 1) In-situ study of processes in Pulsed Laser Epitaxy (PLE) to unveil the roles of individual species with disparate surface diffusion rates on growth, 2) Tuning the composition of ferroelectric thin films to engineer domain orientation, bias, and switching behavior, and 3) Dynamic exploration of polarization and domain structure in ferroelectric superlattices as a function of thin film thickness and electrostatic and strain boundary conditions. Utilizing coherent X-ray scattering methods, the project aims to probe spatiotemporal correlations that are not readily accessible by other means, thereby contributing significantly to the intellectual depth of the field.This project is jointly funded by Ceramics Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.

第1部分：非技术摘要射线是探索材料的强大工具，可以通过衍射来测量原子结构，这是由于其短波长以及它们在没有强吸收的情况下穿透材料的能力。在X射线源中，同步基因是科学家可用的最聪明的。该项目采用实时X射线散射来研究金属氧化物的结构和特性，以其出色的电气和磁性特性而闻名。研究人员的目的是通过密切研究其生长过程，以薄膜的特定关注来揭示这些材料的全部潜力。薄膜可能会引起与胶片衍生的散装母体化合物中的特性显着不同。通过在生长过程中不断捕获不断发展的X射线散射模式，团队在从蒸气相中组装的晶体层的原子结构中获得了见解。这种理解对于创建具有增强或全新特性的创新材料至关重要，包括能够通过晶体晶格（铁电效应）的正和负离子移动来存储电荷或在变形下产生电压（Piezoelectric效应）。这种效果以及其他更奇特的效果可以通过人为产生的薄膜的生长来量身定制，例如那些具有两种不同材料的交替层的薄膜，每个材料都只有几个原子厚。金属氧化物的独特特性在电子记忆，探测器，执行器和能量收割机中发现了应用。除了科学的影响之外，该项目还通过为研究生提供动手培训并让大学生参与尖端研究，在教育和多样性中发挥着至关重要的作用。第2部分：技术摘要该项目探讨了围绕生长过程对金属氧化物薄膜的结构，接口和功能特性的影响的基本问题。超越了实现高质量电影的常规目标，重点是发现独特的增长模式和界面，这些模式和界面可能导致与散装母体化合物中观察到的属性显着不同。该项目集成了对铁电膜的互补测量，以在合成，结构表征和产生的材料特性之间建立反馈回路，从而可以与常规材料的基线特性进行比较。该研究计划包括三个关键追求：1）对脉冲激光外观（PLE）的过程的原位研究，以揭示具有不同表面扩散速率在生长中的单个物种的作用，2）调整铁电薄膜的组成，对工程域的偏置，偏置和切换行为和3）的作用，并构成了偏置和3）的作用。薄膜的厚度和静电边界条件。该项目利用相干的X射线散射方法，旨在探测不容易通过其他方式访问的时空相关性，从而显着促进了该领域的智力深度。该项目由Ceramics计划共同资助。该项目由既定的计划（通过竞争性研究（EPSCOR）进行了启发，并以NSF的奖励进行了反映，并以NSF的奖励进行了反映。智力优点和更广泛的影响审查标准。