NER: Controlled Synthesis of Carbon Nantotubes with Desired Properties

摘要提案题目：NER：具有所需性能的碳纳米管的受控合成提案编号：cts -0508434主要研究者：Renu sharm机构：亚利桑那州立大学分析（决策的理由）：由于碳纳米管的结构变化导致了机械和电气性能的多样化，因此人们对使用碳纳米管作为微型机器，扫描探针，纳米电路和生物传感器的元件非常感兴趣。合成足够数量的具有目标结构和一系列特性的纳米管仍然是一个挑战。在环境高分辨率透射电子显微镜（ETEM）下，采用可控原位催化化学气相沉积（CVD）技术合成了碳纳米管。催化剂也将在同一仪器中通过电子束诱导沉积制备。通过对催化剂分散和纳米管合成条件的控制，以及在亚纳米尺度上观察和物理表征新兴结构的能力，将获得对纳米管合成过程的新见解。第一性原理电子结构计算，结合结构模型，将探讨催化剂颗粒取向如何影响生长方向和生长速率。碳在催化剂颗粒表面的扩散也将被模拟。研究目标是阐明选择性合成包括单壁碳纳米管（SWCNTs）在内的理想碳纳米管类型的方法。碳纳米管的选择性制造将是迈向在纳米级器件中使用纳米管的更广泛目标的重要一步。例如，所开发的技术将在平板显示器或半导体设备的3-D网络的场发射体的直接合成中具有价值。此外，电子束诱导沉积可用于制造量子点阵列。在此开发的组合催化表征技术也将有助于在典型反应温度下在原子水平上研究催化，并将对许多应用的催化剂设计产生影响。展示生长机制的视频影片与模型相结合，为纳米技术本科教育和K-12外展计划提供了宝贵的视觉辅助。

AbstractProposal Title: NER: Controlled Synthesis of Carbon Nanotubes with Desired Properties Proposal Number: CTS-0508434Principal Investigator: Renu SharmaInstitution: Arizona State UniversityAnalysis (rationale for decision):There is great interest in using carbon nanotubes as components in micromachines, scanning probes, nanocircuits and as elements of biosensors since their structural variations give rise to a diverse range of mechanical and electrical properties. Synthesis of sufficient quantities of nanotubes with a targeted structure and set of properties is still a challenge. Carbon nanotubes will be synthesized by controlled in situ catalytic chemical vapor deposition (CVD) in an environmental high-resolution transmission electron microscope (ETEM). The catalyst will also be prepared in the same instrument by electron beam induced deposition. With control over the catalyst dispersion and the nanotube synthesis conditions, as well as the ability to observe and physically characterize the emerging structures at the sub-nanoscale, new insights will be gained into the nanotube synthesis process. First principles electronic structure calculations, in conjunction with structural models, will explore how catalyst particle orientation may contribute to the growth direction and growth rate. The diffusion of carbon through and on the surface of the catalyst particles will also be modeled. The research goal is to elucidate ways to selectively synthesize desirable types of CNT including single-walled CNTs (SWCNTs).The selective fabrication of carbon nanotubes would be an important step towards the broader goal of using nanotubes in nanoscale devices. For example, the techniques developed will be valuable in the direct synthesis of field emitters for flat panel displays or 3-D networks for semiconductor devices. Also, electron beam induced deposition can be used to fabricate arrays of quantum dots. Combinatorial catalysis characterization techniques developed here will also be useful for studying catalysis at the atomic level at typical reaction temperatures, and will have impact in the design of catalysts for many applications. Video movies showing growth mechanisms, combined with models, form invaluable visual aids for undergraduate nanotechnology education as well as for a K-12 outreach program.