Crystal orientation and defect control in active and passive plasmonic systems

非技术描述：贵金属是电子和光学系统中的重要材料，因为它们可以非常容易地传导电流。材料缺陷强烈地决定了这些金属的电子、光学、热和结构特性。到目前为止，缺陷在器件性能中的确切作用还没有被很好地理解，部分原因是没有健壮和可扩展的方法来定义金属结构中的缺陷。这项研究项目旨在调查单个缺陷在黄金器件的电子和光学特性中的作用。这项工作利用了一种新的金属生长技术，以一种简单和可扩展的方式指定单个缺陷。对如何控制和表征贵金属中的缺陷的实验理解为如何使贵金属设备变得更节能、光学响应和机械坚固提供了新的见解。缺陷性质的实验量化也使理论研究人员能够更准确地对器件进行建模。这个项目的教育部分以高中水平的工程教育为目标，通过与实验室的教师合作，为他们提供纳米技术教育的研究视角，并通过研讨会和讨论与高中生接触。技术描述：在这个研究项目中，首席研究员探索了控制单晶金和双晶金金属微结构中晶体取向、晶界取向和晶界位置的方法。这些材料系统作为模型系统来探索缺陷在有源和无源等离子体器件中的作用。一种名为快速熔体生长的晶体生长技术指定了金属中的晶体取向和缺陷。在这项技术中，二氧化硅微熔炉将多晶金和铂种子包裹在一起，黄金首先被加热到熔点，然后被冷却。液相外延是从种子区开始的，是定向的，并以种子晶体为基础确定金属微结构的晶体取向。因此，该方法作为一个通用且可扩展的平台，用于通过光刻图案化来定义金属的晶体性质。例如，金条两端的两个种子结构产生具有一定倾斜边界角度范围的双晶。这位主要研究人员的目标是利用光学和电子显微镜技术，将倾斜边界角等参数与等离子体传输联系起来。该项目的教育部分侧重于高中工程教育，为教师提供纳米技术经验，为学生提供暑期实验室项目和研讨会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical description: Noble metals are important materials in electronic and optical systems because they can conduct electrical currents with exceptional ease. Material defects strongly dictate the electronic, optical, thermal, and structural properties of these metals. To date, the precise role of defects in device performance is not well understood, in part because there do not exist robust and scalable ways to define defects in metallic structures. This research project aims to investigate the role of individual defects in the electronic and optical properties of gold devices. This work leverages a new technique for metal growth that specifies single defects in a simple and scalable way. An experimental understanding of how to control and characterize defects in noble metals provides new insights into how noble metal devices can be made to be more energy efficient, optically responsive, and mechanically robust. Experimental quantification of defect properties also enables theoretical researchers to more accurately model devices. The education component of this project targets engineering education at the high school level, by working with teachers in the lab to provide them with a research perspective in nanotechnology education, and by engaging with high school students through seminars and discussion.Technical description: In this research project, the principle investigator explores methods to control the crystal orientation, grain boundary orientation, and grain boundary position in single- and bi-crystal gold metal microstructures. These material systems serve as model systems to explore the role of defects in active and passive plasmonic devices. A crystal growth technique called rapid melt growth specifies crystal orientation and defects in the metal. In this technique, a silica microcrucible encapsulates polycrystalline gold and a platinum seed, where the gold is first heated to its melting point and is then cooled. Liquid phase epitaxy initiates from the seed region, is directional, and specifies the crystal orientations of the metal microstructures based on the seed crystal. As such, this method serves as a versatile and scalable platform for defining the crystallographic properties of metals through lithographic patterning. For example, two seed structures at each end of a gold stripe produce bi-crystals with a range of tilt-boundary angles. The principle investigator aims to correlate parameters, such as tilt-boundary angle, with plasmon transport, using optical and electronic microscopy techniques. The education component of this project focuses on high school engineering education, by providing teachers with nanotechnology experience and students with summer laboratory programs and seminars.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.