Silicon Carbide Nanocone and Heterostructure Formations Catalyzed by the Release of Carbon-Encapsulated Metal Nanoparticles

技术：本项目主要研究金属催化剂包埋和控释生长纳米结构的生长机理。可控的催化剂释放允许调整催化剂的暴露尺寸/面积，从而导致不寻常的纳米结构的生长，例如由碳化硅制成的纳米锥体。该研究项目的目标是获得金属催化纳米和异质结构形成的所有阶段的新机制知识，包括金属纳米颗粒从碳壳的迁移和团聚行为，金属/纳米锥界面上SiC的形成，异质结构的成核和初始生长。主要研究工具是透射电子显微镜（TEM），将进行原位和非原位TEM实验。电学和性能测量将用于建立合成-结构-性能关系。该项目的潜在成果将是制造具有精确分布和几何形状以及分支结构的特定纳米线的预测工具，以及如何处理条件，如温度，尺寸和催化剂材料类型，将改变纳米线的形态，结构和性能。非技术：该项目涉及对材料科学具有重要意义的主题领域的基础研究问题。它的目的是对控制一维纳米结构形成的催化反应进行定量和机制的理解。这些知识对于基于设计的生产具有特定结构和特性的纳米器件是必要的。该项目通过对纳米科学和纳米技术的博士后、研究生和本科生的培训，构成了研究和教育的有效整合。原位透射电镜纳米表征为学生提供了一个独特的机会。该研究项目还将为纳米技术，特别是纳米制造和纳米表征的研究生课程提供一套新的课程。本科教育将通过本科生暑期研究和高级项目得到加强。

Technical: This project is to study growth mechanism of nanostructures that are grown using encapsulation and controlled release of metal catalyst. The controlled catalyst release allows the exposed size/area of the catalyst be tailored, which leads to growth of unusual nanostructures, such as nanocones made of silicon carbide. The goal of the research project is to gain new mechanistic knowledge of all stages of the metal-catalyzed nano- and hetero-structure formation including the migration of the metal nanoparticle from the carbon shell and agglomeration behavior, the formation of the SiC at the metal/nanocone interface, and the nucleation and initial growth of the heterostructures. The primary research tool is transmission electron microscopy (TEM) and both in-situ and ex-situ TEM experiments will be carried out. Electrical and property measurements will be used to establish the synthesis-structure-property relationships. The potential outcome of the project will be a predictive tool for the manufacturing of specific nanowires with a precise distribution and geometry, as well as branched structures, and how processing conditions, such as temperature, size, and type of catalyst material, will alter the nanowire morphology, structure, and properties.Non-technical: The project addresses fundamental research issues in a topical area of importance to materials science. It aims for a quantitative and mechanistic understanding of the catalytic reaction governing one-dimensional nanostructure formations. Such knowledge is necessary for the design-based production of nanodevices with specific architectures and properties. The project constitutes an effective integration of research and education through training of postdoctoral, graduate, and undergraduate students in nanoscience and nanotechnology. The in-situ TEM nanocharacterization represents a unique opportunity for the students. The research program will also contribute to a new suite of graduate-level courses in nanotechnology, particularly nanofabrication and nanocharacterization. Undergraduate education will be enhanced via undergraduate summer research and senior projects.