Dynamic observation of carbon nanotube growth on isolated catalyst nanoparticles

摘要提案标题：孤立催化剂纳米颗粒上碳纳米管生长的动态观察提案编号：CTS-0625340主要研究者： Renu Sharma机构： 亚利桑那州立大学分析（决策依据）：该提案将研究两步合成具有特定目标结构和性能的碳纳米管的过程。这两个步骤都是独特的，将有助于更广泛地科学理解碳纳米管的合成。在第一步中，将使用电子束诱导沉积（EBID）纳米光刻方法原位制备定制催化剂。定制的EBID制造的催化剂，与颗粒小心地放置在SiO2膜中的孔的边缘，将允许在第二步中导致纳米管的成核和生长的动态事件的无障碍视图。通过乙炔的化学气相分解（CVD）在催化剂颗粒上原位成核和动态生长的碳纳米管将被观察到。这些研究将使用高分辨率（0.2 nm）受控环境（扫描）透射电子显微镜（ESTEM）。此外，纳米衍射数据从亚纳米区域的纳米管和颗粒，以及组成和电子信息的电子能量损失光谱。研究了催化剂粒径、反应温度和压力对纳米管结构的影响。生长机制，然后将使用从头算方法建模，与详细的注意支付的催化剂/纳米管的相互作用。单个纳米管的拓扑结构及其缺陷结构也将被建模。控制纳米管制造的能力将是朝着将其用于构建电路或传感器板的更广泛目标迈出的重要一步。该项目开发的方法也可用于设计其他纳米级器件。例如，电子束诱导沉积可用于制造量子点阵列。本研究中开发的组合催化表征技术也将有助于在典型反应温度下研究原子水平上的催化作用，并可能对其他催化剂的设计产生影响。视频显示的增长机制，结合模型，形成了宝贵的视觉辅助本科纳米技术教育以及亚利桑那州K-12推广计划。首席研究员一直是一个榜样，作为一个成功的科学家从一个代表性不足的群体在亚利桑那州立大学的本科课程。

AbstractProposal Title: Dynamic Observation of Carbon Nanotube Growth on Isolated Catalysts Nanoparticles Proposal Number: CTS-0625340Principal Investigator: Renu SharmaInstitution: Arizona State UniversityAnalysis (rationale for decision):This proposal will investigate a two-step process to synthesize carbon nanotubes having specific targeted structures and properties. Both of these steps are unique and will contribute to a wider scientific understanding of carbon nanotube synthesis. In the first step, a custom catalyst will be prepared in situ using an electron beam induced deposition (EBID) nanolithographic method. The custom EBID-fabricated catalysts, with particles carefully placed at the edges of holes in a SiO2 film, will allow unobstructed views of the dynamical events leading to nucleation and growth of nanotubes during the second step. The in situ nucleation and dynamic growth of carbon nanotubes via chemical vapor decomposition (CVD) of acetylene over the catalyst particles will be observed. A high-resolution ( 0.2 nm) controlled environment (scanning) transmission electron microscope (ESTEM) will be used for these studies. In addition nanodiffraction data from sub-nanometer regions of the nanotubes and particles will be obtained, as well as compositional and electronic information by electron energy loss spectroscopy. The effect of catalyst particle size and reaction temperature and pressure on nanotube structure will be determined. Growth mechanisms will then be modeled using ab initio methods, with detailed attention paid to the catalyst/nanotube interactions. The topologies of individual nanotubes and their defect structures will also be modeled.The ability to control the fabrication of nanotubes will be an important step towards the broader goal of using them to building circuits or sensor boards. The methods developed in this project can also be used for designing other nanoscale devices. For example, electron beam induced depositions can be used to fabricate arrays of quantum dots. Combinatorial catalysis characterization techniques developed in this research will also be useful for studying catalysis at the atomic level at typical reaction temperatures, with possible implications for the design of other catalysts. The videos showing growth mechanisms, combined with models, form invaluable visual aids for undergraduate nanotechnology education as well as for the Arizona State K-12 outreach program. The principal investigator has been a role model as a successful scientist from an underrepresented group for the undergraduate program at ASU.