Graphene- and Metal-based Atomically Precise Nanoelectronics

技术：该项目的目标是开发具有原子精确边缘和边界的石墨烯和金属基纳米结构的制造方法，并对这些样品进行全面的变温磁输运测量，以与理论预测进行比较。其他目标包括对所有三个空间维度小于10纳米的石墨烯和金属基器件的科学探索，以及由此量子约束产生的现象，包括方向和宽度相关的能隙的打开，由于无质量石墨烯载流子引起的不寻常的量子约束效应，以及自旋电子应用中感兴趣的石墨烯的半金属行为。该项目的长期目标是1)精确控制这些样品的制造，以避免边缘缺陷（空位）等有害影响，以及2)详细了解它们的物理特性，以便充分利用它们的电子特性。该项目的第二个主题是利用由施加电流、磁场、温度梯度和蒸汽流引起的质量传递过程来实现原子精确的纳米制造。原子尺度质量迁移效应的详细研究将对纳米器件的老化和失效的理解产生广泛的影响，因为这两者是密切相关的。原子精密纳米制造的方法将基于反馈控制的金属收缩电迁移。这种方法可以创建具有原子光滑边缘的金属掩膜，用于定义所有三维尺寸小于10纳米的石墨烯纳米带。金属纳米粒子将用于催化蚀刻石墨烯成纳米带，其边缘平行于碳晶格的明确晶轴。石墨烯点接触将通过直接FCE形成。通过控制FCE过程中产生的热梯度，可以制造出具有集成触点和原子精确侧壁的金属纳米线。在集成加热器提供的热梯度的同时独立控制下进行FCE过程，将寻求具有原子光滑侧壁的微米长的纳米线。热梯度及其演变的细节将以纳米级空间分辨率和100微秒测量。- 1ms时间分辨率。非技术性：项目涉及电子/光子材料科学领域的基础研究问题，具有较高的技术相关性。研究和教育相结合，重点是教育，推广，国际合作，以及对科学和工程相关领域的影响。在一个充满活力和跨学科的研究环境中，将为研究生、本科生和高中生提供培训。pi的推广和教育工作将包括与宾夕法尼亚大学科学教师研究所合作，为他们的教师毕业生提供研究经验，并开发短期课程，以增加高中科学教师的内容知识。费城的K-12社区将参与一年一度的NanoDay@PENN，包括该组织的技术海报和适合普通观众的演讲。研究基础设施将通过与纳米科学非洲网络NanoAFNET的国际伙伴关系得到加强；该项目每年将接待三名对纳米电子学和纳米材料领域有研究兴趣的科学家。

Technical: The goal of the project is to develop fabrication methods for graphene- and metal-based nanostructures with atomically precise edges and boundaries, and to perform comprehensive variable-temperature magnetotransport measurements on these samples for comparison with theoretical predictions. Other goals include the scientific exploration of graphene- and metal-based devices with all three spatial dimensions smaller than 10 nm, and phenomena derived from this quantum confinement, including the opening of an orientation- and width-dependent energy gap, unusual quantum confinement effects due to the massless graphene charge carriers, and half-metallic behavior of graphene of interest for spintronic applications. Long-term objectives of the project are 1) precise control over the fabrication of such samples so that the deleterious effects of edge defects (vacancies) and the like can be avoided, and 2) a detailed understanding of their physics so that the full power of their electronic properties can be harnessed. A second theme of the project is the use of mass transport processes due to applied currents, magnetic fields, temperature gradients, and vapor flow to achieve atomically precise nanofabrication. This detailed investigation of atomic scale mass migration effects will have broad impact on the understanding of aging and failure of nanoscale devices, as the two are closely linked. Methods of atomically precise nanofabrication will be based on Feedback Controlled Electromigration of metal constrictions. This method may enable creation of metal masks with atomically smooth edges that will be used to define graphene nanostrips with all three dimensions smaller than 10 nm in size. Metal nanoparticles will be used to catalytically etch graphene into nanoribbons whose edges run parallel to well defined crystal axes of the carbon lattice. Graphene point contacts will be formed by direct FCE. Metal nanowires with integrated contacts and atomically precise sidewalls will be fabricated by controlling thermal gradients that develop during FCE. Micrometer-long nanowires with atomically smooth sidewalls will be sought by performing the FCE process with simultaneous independent control of thermal gradients provided by integrated heaters. Details of the thermal gradients and their evolution will be measured with nanoscale spatial resolution and 100 microsec. - 1 ms time resolution. Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. Research and education are integrated with emphasis in education, outreach, international collaboration, and impact on related fields in science and engineering. Training will be provided to graduate students, undergraduates, and high school students in a dynamic and interdisciplinary research environment. Outreach and education efforts by the PIs will include a partnership with the Penn Science Teachers Institute to provide research experiences for their teacher graduates and to develop short courses to increase the content knowledge of high school science teachers. Philadelphia's K-12 community will be engaged through participation in the annual NanoDay@PENN, including technical posters from the group and presentations appropriate for a general audience. Research infrastructure will be enhanced through an international partnership with NanoAFNET, the Nanosciences African Network; the project will host up to three scientists per year with research interests in the area of nanoelectronics and nanomaterials.