Strain-Induced Ordering, Assembly, and Defects in Nanoscale Thin-Film Heterostructures

纳米级薄膜异质结构中应变诱导的有序、组装和缺陷

• 批准号: 1300223
• 负责人: Yanfei Gao
• 金额: $ 26.8万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1300223&HistoricalAwards=false
• 关键词: Strain; Induced; Ordering; Assembly; Defects

The research objective of this award is to identify and investigate fundamental modeling issues in a simultaneous thin film growth and self-assembly process, in which phase separation as well as self-assembly of nanoscale heterostructure occur simultaneously during the growth of thin film. A successful fabrication process for ordered arrays of nanostructures in multi-phase thin films would find applications in a wide variety of material systems such as superconductors and multiferroics. Key hypotheses underpinning the fundamental behavior will be investigated including (1) vertical/lateral ordering and self-assembly is strain mediated; (2) control of these nanostructures relies on the competition between several kinetic processes; and (3) resulting functional properties depend on defects in thin film heterostructures. The proposed work will develop a theoretical model and phase-field simulations that consider the evolution of composition (phase separation), morphology (film growth), defects, and polarization (domain switching). The predicative capabilities will be tested by close collaborations with experimental groups. The grand challenge arising from the synthesis and applications of multi-functional materials is how to achieve patterned and ordered nanostructures with one or multiple length scales that are commensurate with the designed functional properties. As a critical step towards this direction, this program helps establish a centralized platform for focused research and education activities in the fields of novel materials processing, reliability, and multifunctional properties at small scales, which are beyond the current curricula and educational means in materials science and applied mechanics. The educational plan focuses on new curriculum development in nanomaterials and active participation in the UT Math and Science Center (targeting high school students from rural counties in East Tennessee) and the UT Pre-Collegiate Research Scholars program (targeting high school students in Knox County). These activities will have a particular emphasis on educating students from underrepresented groups.

该奖项的研究目标是在同时薄膜的增长和自组装过程中识别和研究基本建模问题，在薄膜的生长过程中，同时出现了纳米级异质结构的相分离以及自组装。多层薄膜中有序的纳米结构阵列的成功制造过程将在各种材料系统（例如超导体和多效体）中找到应用。将研究基本行为的关键假设，包括（1）垂直/横向订购和自组装是介导的应变； （2）控制这些纳米结构取决于几个动力学过程之间的竞争； （3）由此产生的功能特性取决于薄膜异质结构中的缺陷。提出的工作将开发一个理论模型和相位模拟，该模型考虑组成（相位分离），形态（膜生长），缺陷和极化（域切换）的演变。谓词功能将通过与实验组的密切合作进行测试。多功能材料的合成和应用带来的巨大挑战是如何实现具有一个或多个长度尺度的模式和有序的纳米结构，这些纳米结构与设计的功能性能相称。作为朝着这一方向发展的关键一步，该计划有助于建立一个集中的平台，以在小规模的新型材料处理，可靠性和多功能属性领域的集中研究和教育活动中，这超出了当前的课程和材料科学的教育手段和应用力学。该教育计划重点介绍纳米材料的新课程开发，并积极参与UT数学和科学中心（针对田纳西州农村县的高中生）和UT前学会的研究学者计划（针对诺克斯县的高中生） 。这些活动将特别强调从代表性不足的群体中教育学生。