Nucleation and Growth of Single-Walled Carbon Nanotubes Catalyzed by Transition Metal Particles

技术概述：该奖项支持理论物理学领域的研究和教育，该领域涉及过渡金属颗粒催化的单壁碳纳米管（SWCNT）的成核和生长。这项研究的动机是这些系统不同寻常的材料特性，特别是它们卓越的电学、机械、热学和光学特性。SWCNTs是最好的电和热导体，具有优异的光物理和化学性质。该研究旨在提供一些在创建这些材料时发生的过程的基本理解，以便实现SWCNTs的潜在应用。特别强调的领域包括这些材料的成核和生长，但在这个过程中，研究人员将确定加工途径，使控制手性和swcnts的直径成为可能，这两个重要参数决定了swcnts是半导体还是金属。研究人员将使用理论和计算机模拟技术来更好地了解SWCNTs的生长过程，以及如何在控制直径、手性、长度和壁结构的情况下实现所需的相干和无缺陷SWCNTs的均匀性。本研究将重点分析和描述催化CVD技术，这是三种大规模生产SWCNTs的主要技术中最有前途的技术。计算机模拟将提供对生长过程的深入了解，这些过程很难通过实验监测，因为它们发生在比室温高得多的温度下，大约在400 ？尽管采用了先进的纳米级测量技术，但1000千牛顿的高温导致高压，增加了监测实验过程中涉及的原子水平动力学的难度。因此，计算研究是必要的，以便检查SWCNTs的生长阶段，并为更可控的SWCNTs生长铺平道路。为了了解决定SWCNTs手性和直径的因素和参数，必须进行严格的量子力学模拟。我们打算表演全部？电子密度泛函理论（DFT）在广义梯度近似水平（GGA）的模拟。这些计算将作为从头算分子动力学（MD）计算的基准，该计算可以处理比所有电子DFT模拟更大的系统以及有限温度计算。在这些模拟的最后阶段，紧密结合的分子动力学计算将在更大的系统和更大的时间尺度上进行，而不是从头算md。所提出的工作具有超越基础研究的教育和应用影响。在科学方面，该奖项将影响佛罗里达农工大学（FAMU）开发碳基技术的相关研究和应用工作。计算工作将补充FAMU纳米科学和纳米技术中心SWCNTS生长的实验工作。拟议的工作还将补充FAMU高性能计算中心的发展，该中心正在购置一组计算机用于高性能计算和模拟。这对教育的影响包括计算纳米科学课程的发展。这项工作支持少数民族参与科学。FAMU是主要的hbcu之一，拥有四个物理学博士学位之一，这笔拨款将用于支持少数民族学生的培训。该研究具有很强的教育成分，涉及研究生的培训，并延续了PI长期以来招募本科生进行尖端研究项目并发表成果的历史。非技术总结：该奖项支持理论物理领域与单壁碳纳米管（SWCNT）成核和生长相关的研究和教育。这些超小型管被视为未来纳米器件的关键元素之一。这项研究的动机是这些系统不同寻常的材料特性，特别是它们卓越的电学、机械、热学和光学特性。SWCNTs是最好的电和热导体，具有优异的光学和化学性能。该研究旨在提供一些在创建这些材料时发生的过程的基本理解，以便实现SWCNTs的潜在应用。特别强调的领域包括这些材料的成核和生长，但在这个过程中，研究人员将确定加工途径，使控制swcnts的结构和决定swcnts如何导电的参数成为可能。研究人员将使用理论和计算机模拟技术来更好地了解SWCNTs的生长过程，以及如何在控制直径、长度和壁结构的情况下实现所需的均匀性和无缺陷的SWCNTs。本研究将主要集中于分析和描述最有前途的SWCNTs大规模生产技术。计算机模拟将提供对生长过程的深入了解，因为生长过程发生在比室温高得多的温度和高压下，这增加了监测实验的难度，尽管有先进的纳米级测量技术。因此，有必要进行计算研究，以检查生长的各个阶段，并为更可控的SWCNTs生长铺平道路。所提出的工作具有超越基础研究的教育和应用影响。在科学方面，该奖项将影响佛罗里达农工大学（FAMU）开发碳基技术的相关研究和应用工作。计算工作将补充FAMU纳米科学和纳米技术中心SWCNTS生长的实验工作。拟议的工作还将补充FAMU高性能计算中心的发展，该中心正在购置一组计算机用于高性能计算和模拟。这对教育的影响包括计算纳米科学课程的发展。这项工作支持少数民族参与科学。FAMU是主要的hbcu之一，拥有四个物理学博士学位之一，这笔拨款将用于支持少数民族学生的培训。该研究具有很强的教育成分，涉及研究生的培训，并延续了PI长期以来招募本科生进行尖端研究项目并发表成果的历史。

TECHNICAL SUMMARY:This award supports research and education in theoretical physics in an area related to nucleation and growth of single-walled carbon nanotubes (SWCNT) catalyzed by transition metal particles. The study is motivated by the unusual materials properties of these systems, particularly their remarkable electrical, mechanical, thermal and optical properties. SWCNTs are the best conductors of electricity and heat and have exceptional photophysical and chemical properties. The research intends to provide some of the essential understanding of the processes that occur in creating these materials so that the potential applications of SWCNTs may be realized. The area of particular emphasis includes the nucleation and growth of these materials but in the process researcher will identify processing avenues that make it possible to control the chirality and diameter of a SWCNT, two important parameters that determine whether a SWCNT is semiconducting or metallic.Researchers will use theoretical and computer simulation techniques to better understand the growth process of SWCNT and how to achieve the desired uniformities of coherent and defect-free SWCNTs with controlled diameter, chirality, length and wall structure. This research will focus mainly on analyzing and describing catalyzed CVD technique, which is the most promising of the three major techniques for mass production of SWCNTs. Computer simulations will provide insight into the growth processes which are difficult to monitor experimentally because they occur at temperatures much higher than room temperature, in the range of approximately 400 ? 1000 Kn where the high temperature results in a high pressure, adding to the difficulty of monitoring the atomic level dynamics involved during the experiment despite advanced nanoscale measuring techniques. Computational studies are therefore necessary in order to examine the stages of the growth and pave the way for a more controlled growth of SWCNTsIn order to understand the factors and parameters determining the chirality and diameter of the SWCNTs, rigorous quantum mechanical simulations must be done. We intend to perform all?electron density functional theory (DFT) simulations at the generalized gradient approximation level (GGA). These calculations will serve as benchmarks for ab initio molecular dynamics (MD) calculations which can handle larger systems than the all electron DFT simulations as well as finite temperature calculations. In the final stage of these simulations tight binding molecular dynamics calculations will be performed for larger systems and larger time scales than ab initio MD.The proposed work has both educational and applied impact beyond the basic research. Scientifically, this award will impact related research and applied work to develop carbon based technology at Florida A & M University (FAMU). The computational work will complement the experimental work in the growth of SWCNTS at FAMU Center for Nanoscience and Nanotechnology. The proposed work also will complement the development of the FAMU High Performance Computing Center where a computer cluster is being acquired for high performance computing and the simulations. The educational consequence of this includes the development of computational nanoscience coursework. Participation of minorities in science is supported through this effort. FAMU, one of the leading HBCUs, has one of the four Ph. Ds in physics and this grant will support the training of minority students. The research that has a strong education component involving the training of graduate students and a continuation of the PI's long history of recruiting undergraduates in cutting edge research projects with publishable outcomes.NON-TECHNICAL SUMMARY:This award supports research and education in theoretical physics in an area related to nucleation and growth of single-walled carbon nanotubes (SWCNT). These ultra small tubes are seen as one of the key elements of future nanodevices. The study is motivated by the unusual materials properties of these systems, particularly their remarkable electrical, mechanical, thermal and optical properties. SWCNTs are the best conductors of electricity and heat and have exceptional optical and chemical properties. The research intends to provide some of the essential understanding of the processes that occur in creating these materials so that the potential applications of SWCNTs may be realized. The area of particular emphasis includes the nucleation and growth of these materials but in the process researchers will identify processing avenues that make it possible to control the structure of a SWCNT and the parameters that determine how a SWCNT is conducts electric current.Researchers will use theoretical and computer simulation techniques to better understand the growth process of SWCNT and how to achieve the desired uniformities and defect-free SWCNTs with controlled diameter, length and wall structure. This research will focus mainly on analyzing and describing the most promising techniques for mass production of SWCNTs. Computer simulations will provide insight into the growth processes which are difficult to monitor experimentally because they occur at temperatures much higher than room temperature, and at high pressure, adding to the difficulty of monitoring the experiments despite advanced nanoscale measuring techniques. Computational studies are therefore necessary in order to examine the stages of the growth and pave the way for a more controlled growth of SWCNTs.The proposed work has both educational and applied impact beyond the basic research. Scientifically, this award will impact related research and applied work to develop carbon based technology at Florida A & M University (FAMU). The computational work will complement the experimental work in the growth of SWCNTS at FAMU Center for Nanoscience and Nanotechnology. The proposed work also will complement the development of the FAMU High Performance Computing Center where a computer cluster is being acquired for high performance computing and the simulations. The educational consequence of this includes the development of computational nanoscience coursework. Participation of minorities in science is supported through this effort. FAMU, one of the leading HBCUs, has one of the four Ph. Ds in physics and this grant will support the training of minority students. The research that has a strong education component involving the training of graduate students and a continuation of the PI's long history of recruiting undergraduates in cutting edge research projects with publishable outcomes.