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传输测量，以便与理论预测进行比较。其他目标包括科学探索所有三个空间尺寸都小于10 nm的石墨烯和金属器件，以及由这种量子限制产生的现象，包括打开与取向和宽度有关的能隙，由于无质量的石墨烯电荷载流子而产生的不寻常的量子限制效应，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)精确控制此类样品的制造，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使用由于外加电流、磁场、温度梯度和蒸汽流动而产生的质量传输过程来实现原子精确的纳米制造。这种对原子尺度质量迁移效应的详细研究将对理解纳米器件的老化和失效产生广泛的影响，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金属收缩的反馈控制电迁移。这种方法可以创建具有原子平滑边缘的金属掩模，该掩模将用于定义所有三个维度的尺寸都小于10 nm的石墨烯纳米带。金属纳米颗粒将被用来催化蚀刻石墨烯成纳米带，其边缘平行于定义良好的碳晶格的晶轴。石墨烯的点接触将由直接的FCE形成。通过控制FCE过程中产生的温度梯度，将制造具有集成接触和原子精确侧壁的金属纳米线。具有原子光滑侧壁的微米长纳米线将通过执行FCE工艺并同时独立控制集成加热器提供的温度梯度来寻找。温度梯度及其演化的细节将以纳米级的空间分辨率和100微秒进行测量。-1毫秒时间分辨率。非技术性：该项目涉及具有高度技术相关性的电子/光子材料科学专题领域的基础研究问题。研究与教育相结合，重点放在教育、推广、国际合作以及对科学和工程相关领域的影响方面。将在动态和跨学科的研究环境中为研究生、本科生和高中生提供培训。PIS的外联和教育工作将包括与宾夕法尼亚大学科学教师学院合作，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教学知识。费城的K-12社区将通过参加一年一度的NanoDay@Penn参与进来，包括该组织的技术海报和适合普通观众的演示。研究基础设施将通过与非洲纳米科学网络NanoAFNET的国际伙伴关系得到加强；该项目每年将接待多达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.