Materials World Network: Novel Strain Control in Thick Epitaxial Nancomposite Films

这个材料世界网络项目探索外延薄膜形式的垂直应变控制纳米复合材料(VSCN)系统的生长、结构和物理性能。这项拟议的研究为两相纳米复合材料中的晶格应变控制开辟了一条全新的途径，通过这种方法，纳米柱可以相互垂直控制应变，而不依赖于界面。与横向异质外延系统相比，VSCN系统中界面控制的消除允许生长更厚的应变薄膜(300 Nm)，从而允许一系列新型功能器件的可能性。该项目涉及英国德克萨斯农工大学(王博士)和剑桥大学(德里斯科尔博士)之间的广泛合作。该联合项目的目标是为新的应用而生长和理解VSCN外延薄膜。目标包括：1)开发一套用于预测可能的两相纳米复合系统的指南；2)利用互补沉积技术来生长所预测系统的薄膜；3)确定控制VSCN结构的因素；以及4)展示一到两种单相性能增强或新颖的多功能。这种跨学科的努力结合了两所大学的研究专业知识。新的VSCN系统将首先使用化学气相沉积(CVD)(剑桥)，然后是脉冲激光沉积(PLD)(得克萨斯州)。各种表征技术，如高分辨率X射线衍射仪(剑桥)和透射电子显微镜(结合STEM和EELS成分分析，德克萨斯州)，以及电磁性能测量，将被用来研究这些VSCN系统的结构和功能特性。这项研究的学术价值是对VSCN系统中垂直应变控制的基本理解，它允许应变层的生长远远超过传统的临界厚度。该项目将产生广泛的影响，1)为参与该项目的研究人员提供国际多学科培训，2)加强两所大学的材料科学和工程课程。研究成果将通过以下方式迅速传播给更广泛的受众：(A)让高中教师参与这个研究项目，(B)让材料科学和工程领域中代表性不足的群体参与，以及(C)通过两所大学提供的外展计划吸引高中生参加材料科学项目。

This Materials World Network project explores the growth, structure and physical properties of vertically strain-controlled nanocomposite (VSCN) systems in epitaxial thin film form. The proposed research opens the door to a brand-new avenue for lattice strain control in two-phase nanocomposites, whereby the nanocolumns control the strain vertically in one another, independent of the interface. The elimination of interface control in the VSCN systems allows much thicker strained films (300 nm) to be grown compared to lateral heteroepitaxial systems and thus allows a whole range of novel functional device possibilities. This project involves extensive collaboration between Texas A & M University (Dr. Wang) and the University of Cambridge (Dr. Driscoll) in the United Kingdom.The goal of this joint program is to grow and understand VSCN epitaxial films for novel applications. The objectives include: 1) to develop a set of guidelines for predicting possible 2-phase nancomposite systems; 2) to utilize complementary deposition techniques to grow films of the predicted systems; 3) to determine the factors which control the VSCN architectures; and 4) to demonstrate one or two single phase property enhancements or novel multifunctionalities. This interdisciplinary effort combines research expertise from both universities. Novel VSCN systems will first be explored using chemical vapor deposition, CVD (Cambridge) and then, pulsed laser deposition, PLD (Texas). Various characterization techniques, such as high resolution XRD (Cambridge) and TEM (combined with STEM and EELS compositional analysis, Texas), as well as electrical and magnetic property measurements, will be utilized to investigate the structural, and functional properties of these VSCN systems. The intellectual merit of the proposed research is the fundamental understanding of vertical strain-control in VSCN systems, which allows growth of strained layers far in excess of the conventional critical thickness. The project will have broad impact by 1) offering international multidisciplinary training to the researchers involved in the program and 2) enhancing the materials science and engineering curricula at both universities. The research results will be quickly disseminated to a much broader audience by (a) involving high school teachers in this research project, (b) involving under-represented groups in materials science and engineering and (c) attracting high school students into Materials Science program through the outreach programs available at both universities.