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

技术：本项目旨在研究利用金属催化剂的包裹和控制释放来生长纳米结构的生长机理。受控的催化剂释放允许定制催化剂暴露的大小/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结构和异质结构形成的所有阶段的新的机理知识，包括金属纳米颗粒从碳壳中的迁移和团聚行为，金属/纳米锥界面上的碳化硅的形成，以及异质结构的形核和初始生长。主要的研究工具是透射电子显微镜，将进行原位和非原位的透射电子显微镜实验。将使用电学和性能测量来建立合成-结构-性能关系。该项目的潜在成果将是一种预测工具，用于制造具有精确分布和几何形状的特定纳米线以及分支结构，以及加工条件，如温度、尺寸和催化剂材料的类型，将如何改变纳米线的形态、结构和性能。非技术性：该项目解决了对材料科学具有重要意义的主题领域的基础研究问题。它的目的是从定量和机理上理解支配一维纳米结构形成的催化反应。这些知识对于以设计为基础的具有特定结构和特性的纳米器件的生产是必要的。该项目通过培训纳米科学和纳米技术的博士后、研究生和本科生，有效地整合了研究和教育。原位透射电子显微镜纳米表征对学生来说是一个独特的机会。该研究计划还将为一套新的研究生级别的纳米技术课程做出贡献，特别是纳米制造和纳米表征。本科教育将通过本科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.