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

该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。这项研究为两相纳米复合材料的晶格应变控制开辟了一条全新的途径，即纳米柱相互垂直控制应变，与界面无关。在VSCN系统中的界面控制的消除允许更厚的应变膜（300纳米）相比，横向异质外延系统生长，从而允许一个新的功能器件的可能性的整个范围。该项目涉及得克萨斯A M大学（王博士）和英国剑桥大学（Drivel博士）之间的广泛合作。该联合计划的目标是生长和理解用于新应用的VSCN外延膜。&这些目标包括：1）开发一套准则，用于预测可能的2相纳米复合材料系统; 2）利用互补沉积技术来生长预测系统的薄膜; 3）确定控制VSCN结构的因素;以及4）证明一个或两个单相性能增强或新的多功能性。这种跨学科的努力结合了两所大学的研究专长。新型VSCN系统将首先使用化学气相沉积（CVD）（剑桥）进行探索，然后使用脉冲激光沉积（PLD）（德克萨斯）进行探索。各种表征技术，如高分辨率XRD（剑桥）和TEM（结合STEM和EELS成分分析，得克萨斯州），以及电和磁性能测量，将被用来研究这些VSCN系统的结构和功能特性。 所提出的研究的智力价值是在VSCN系统中的垂直应变控制的基本理解，这使得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）为参与该计划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。研究结果将迅速传播到更广泛的受众（a）涉及高中教师在这个研究项目，（B）涉及材料科学和工程的代表性不足的群体和（c）吸引高中学生进入材料科学计划通过在两所大学提供的推广计划。

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.