Fabrication and Optimization of Highly Ordered Assemblies of Metallic Nanowire and Nanoparticle Arrays

国家科学基金会-化学运输系统分部颗粒多相过程计划（1415）提案编号：0731349主要研究者：Ragan，Regina隶属机构： 加州尔湾大学提案标题：金属纳米线和纳米颗粒阵列的高度有序组装的制造和优化硅衬底上的金属/稀土二硅化物核-壳纳米结构阵列，除了均匀的尺寸和形状外，还具有高密度，将被设计、建模和表征用于并入生物传感器系统。虽然贵金属纳米结构在生物传感器中表现出了非凡的单分子检测极限能力，但利用其独特性质的技术发展的最重大挑战之一是使用低成本和高通量技术制造具有单分散尺寸，形状和高密度的阵列。最近，主要研究者已经开发出一种独特的超大规模兼容的制造工艺，用于在Si衬底上的单分散Pt和Au核壳纳米结构的致密（~1011 cm-2）有序阵列。Pt和Au原子在自组装纳米线模板上的物理气相沉积，随后反应离子蚀刻产生平均粒径小于10 nm、窄尺寸分布1 nm和~ 10 nm的颗粒间间距的贵金属/稀土二硅化物核-壳纳米结构阵列，而无需光刻。.制作：初步结果表明，所提出的合成路线产生的Pt和Au纳米结构的自组装稀土二硅化物纳米线上的Si（001）衬底。这种成功的制备技术将被应用于制备Ag和其他金属核壳结构，以在不同的频率范围内调谐光学响应。.理论：将进行自组装模板的表面原子结构、它们与Si（001）表面的界面以及纳米线模板表面上的贵金属原子聚集的理论计算。我们的目标是了解装配机制，以优化结构，使我们的工艺可转化为其他材料系统。表征：表面结构和电子状态的原子水平分辨率将通过STM和光谱学进行研究。智力优势：直径远小于光的波长和窄的粒子间间距的金属纳米结构由于这些粒子周围的电磁场的局部增强而具有强的近场耦合。我们将在此背景下解决基本问题：1）阵列中纳米结构的排列如何影响信号增强; 2）如何有效地在大表面上图案化纳米结构。采用微电子加工方法并结合自组装和光刻技术在硅衬底上以阵列形式制造单分散金属纳米结构是该提议的独特之处。通过自组装工艺，特征尺寸为8 nm，可实现的颗粒间间距为~10 nm，小于用电子束光刻获得的特征尺寸，并且产量高得多;因此可以获得独特的光学特性。协同的理论和实验研究将允许高效和合理的优化，并最终大规模生产的纳米结构的生物传感器应用。更广泛的影响：创新和高通量的纳米结构阵列的制造技术是许多新兴技术，如纳米催化，自旋电子学，量子计算和光化学的重要。这项基础研究将为成功制造高密度、均匀分散的纳米结构阵列铺平道路，这些纳米结构阵列可用于生物传感器应用。我们提出的制造技术显然可用于其他应用，并且由于与当前半导体制造技术的兼容性，可以扩展到大面积进行大规模生产。该提案还将通过研究机会和外联活动支持对高中生、本科生和研究生的继续培训。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0731349 Principal Investigators: Ragan, Regina Affiliation: University of California Irvine Proposal Title: Fabrication and Optimization of Highly Ordered Assemblies of Metallic Nanowire and Nanoparticle Arrays Metal/rare earth disilicide core-shell nanostructure arrays on silicon substrates that have high density in addition to uniform size and shape will be designed, modeled, and characterized for incorporation into biosensor systems. Although noble metal nanostructures have demonstrated extraordinary capacity for single molecule detection limits in biosensors, one of the most significant challenges to technological developments that capitalize on their unique properties is the fabrication of arrays with monodisperse size, shape and high density using a low cost and high throughput technique. Recently, the principal investigator has developed a unique ultralarge scale compatible fabrication process for dense (~1011 cm-2) ordered arrays of monodisperse Pt and Au coreshell nanostructures on Si substrates. Physical vapor deposition of Pt and Au atoms on self-assembled nanowire templates followed by reactive ion etching produces noble metal/rare earth disilicide core-shell nanostructure arrays with mean particle diameter of less than 10 nm, a narrow size distribution, 1 nm, and inter-particle spacing of ~ 10 nm without lithography. . Fabrication: Preliminary results demonstrate that the proposed synthesis route produced both Pt and Au nanostructures on self-assembled rare earth disilicide nanowires on Si(001) substrates. This successful fabrication technique will thus be applied to fabricate Ag and other metal core-shell structures in order to tune optical responses in different frequency range. . Theory: Theoretical calculations of surface atomic structures of self-assembled templates, their interfaces with the Si(001) surface, and noble metal atom aggregation on nanowire template surfaces will be performed. The goal is to understand assembly mechanisms in order to optimize structure and make our process translatable to other material systems.. Characterization: Atomic level resolution of surface structures and electronic states will be investigated by STM and spectroscopy. Intellectual Merit: Metal nanostructures with diameters much less than the wavelength of light and narrow interparticle spacing have strong near field coupling due to a local enhancement of the electromagnetic field around these particles. We will address fundamental questions in this context: 1) how the arrangement of nanostructures in arrays affects signal enhancements; and 2) how to effectively pattern nanostructures over a large surface. Fabrication of monodisperse metal nanostructures in array format on Si substrates using microelectronic processing methods and combining self- assembly with lithography is unique to this proposal. Through the self-assembly process, the feature size, 8 nm, and inter-particle spacing achievable, ~10 nm, are smaller than that obtained with electron beam lithography and the throughput is much higher; thus unique optical properties can be attained. The synergistic theoretical and experimental studies will allow efficient and rational optimization and eventually massive production of nanostructures for biosensor applications.Broader Impact: Innovative and high-throughput fabrication techniques of nanostructure arrays are significant for many emerging technologies such as nanocatalysis, spintronics, quantum computing and optochemistry. This proposed fundamental study will pave the way for successful fabrication of high density, uniformly dispersed, nanostructure arrays optimized for biosensor applications. Our proposed fabrication technique is apparently translatable for other applications and affords the possibility to scale to large areas for massive production due the compatibility with current semiconductor manufacturing technology. This proposal will also support the continued training of high school, undergraduate and graduate students through research opportunities and outreach activities.