GOALI: Design and Fabrication of a Hybrid Drift Diffusion Spin Valve to Investigate Graphene Spin Transport Properties for Spintronics

电子学是基于对电子和其他电荷载体的操纵。除了电荷，电子的自旋可以通过磁场和电场来操纵，导致自旋极化电流携带的信息比单独使用电荷时可能携带的信息更多。自旋输运电子学在设计新型器件方面显示出了克服传统电子学局限性的优势。石墨烯是石墨化碳的单原子层，具有独特的物理性质，使其在自旋电子应用中非常有吸引力。通过将石墨烯与其他类型的材料，包括铁磁材料、半导体和金属电极相连接，已经实现了石墨烯中自旋输运的各种实验演示。然而，实验结果仍远低于理论预测值。为了弥补这一差距，提出了两个领域的研究：石墨烯的制造和一种新型器件的设计，以促进基于石墨烯的自旋电子器件的发展，该器件将能够实现更高的数据传输速度、更高的处理能力和存储密度以及更大的存储容量。PSU和英特尔的合作将大大加强研究成果向业界的转移。它还将扩大相关研究生和本科生的培训和经验，促进PSU和英特尔科学家之间的积极互动，并在新兴材料科学和设备技术领域对他们进行培训，在这些领域，基本的见解可以带来深刻而快速的实践进步。该项目将通过NSF正在进行的REU和LSAMP项目、McNair奖学金项目以及巴黎州立大学的本科生研究和指导项目来利用未被充分代表的本科生的参与。该提案旨在通过适用于行业的工艺设计和制造新型混合扩散漂移自旋阀(HDDSV)阵列。该装置将允许系统地研究石墨烯的自旋输运参数，包括自旋寿命、自旋扩散长度和极化注入效率。用来研究石墨烯自旋输运的非局域自旋阀(NLSV)装置得到的实验值比理论预测值低了几个数量级。所提出的HDDSV被独特地设计用于检测源自自旋极化载流子的自旋积累的非局部信号，该信号发生在远离铁磁(FM)/隧道势垒(TB)/石墨烯界面的影响的地方。这项研究工作代表了一种结合石墨烯合成、器件制造以及数据测量和分析的多学科方法，以促进对石墨烯自旋输运性质的理解。这项研究的总体目标是解决石墨烯自旋电子学发展的主要障碍。这种新颖的器件配置将具有将铁磁接触的影响与石墨烯自旋传输测量隔离的能力，同时能够同时操纵自旋和电荷载流子。所提出的装置将允许研究新的自旋转移现象。对这种新型器件的研究将揭示石墨烯输运通道中铁磁接触和载流子漂移与自旋扩散长度和自旋寿命之间的基本效应。学术和工业研究团队的互补专业知识和综合能力保证了拟议目标的成功。

Electronics are based on the manipulation of electrons and other charge carriers. In addition to charge, electrons have spin that can be manipulated with magnetic and electric fields, resulting in a spin-polarized current that carries more information than is possible with charge alone. Spin-transport electronics demonstrate advantages for design of novel devices to overcome the limitation of traditional electronics. Graphene, a single atomic layer of graphitic carbon, has unique physical properties that make it very attractive for spintronic applications. Various experimental demonstrations of spin transport in graphene have been achieved by interfacing graphene with other classes of materials, including ferromagnetic materials, semiconductors, and metal electrodes. However, the experimental results are still well below theoretically predicted values. To bridge this gap, two areas of research is proposed: fabrication of graphene and a design of a novel device to advance graphene-based spintronic devices that will be capable of higher data transfer speeds, increased processing power and memory density, and added storage capacity. The PSU and Intel partnership will significantly enhance the transfer of research results to industry. It will also broaden the training and experiences of graduate and undergraduate students involved and facilitate active interactions between PSU and Intel scientists and train them in emerging areas of materials science and device technology, where fundamental insights can result in profound and rapid practical advances. The participation of underrepresented undergraduates in this project will be leveraged through ongoing NSF funded REU and LSAMP programs, the McNair Scholarship program, and the Undergraduate Research and Mentoring Program at PSU.This proposal aims at the design and fabrication of novel hybrid diffusion drift spin valve (HDDSV) arrays through processes that are adaptable to industry. The proposed device will allow systematic investigations of graphene spin transport parameters including spin lifetime, spin diffusion length, and polarization injection efficiency by variations of device components and dimensions. The non-local spin valves (NLSV) device employed to study graphene spin transport has resulted in experimental values that are orders of magnitude lower than those theoretically predicted. The proposed HDDSVs are uniquely designed to detect nonlocal signals originating from a spin accumulation of spin polarized charge carriers, which occurs away from the influence of ferromagnetic (FM)/tunnel barrier (TB)/Graphene interfaces. This research effort represents a multi-disciplinary approach of combining graphene synthesis, device fabrication, and data measurement and analysis, to advance the understanding of graphene spin transport properties. The overall goal of this research is to address the principle roadblocks to the advancement of graphene spintronics. The novel device configuration will have the capability of isolating the effects of ferromagnetic contacts from graphene spin transport measurements, while enabling spin and charge carrier manipulation simultaneously. The proposed device will allow new spin transfer phenomena to be examined. The study of such a novel device will reveal the fundamental effects of ferromagnetic contacts and charge carrier drift in relation to spin diffusion lengths and spin lifetimes in a graphene transport channel. The academic and industrial research teams' complementary expertise and comprehensive capabilities warrant success of the proposed goals.