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，电子还具有自旋，可以用磁场和电场进行操纵，从而产生自旋极化电流，该电流携带的信息比单独使用电荷时更多。自旋输运电子学在设计新型器件以克服传统电子学的局限性方面显示出优势。石墨烯是石墨碳的单原子层，具有独特的物理性质，使其对自旋电子应用非常有吸引力。石墨烯中自旋输运的各种实验证明已经通过将石墨烯与其他种类的材料（包括铁磁材料、半导体和金属电极）界面连接来实现。然而，实验结果仍然远低于理论预测值。为了弥合这一差距，提出了两个研究领域：石墨烯的制造和一种新型器件的设计，以推进石墨烯基自旋电子器件，该器件将能够实现更高的数据传输速度，提高处理能力和存储密度，并增加存储容量。PSU和英特尔的合作伙伴关系将大大加强研究成果向工业界的转移。它还将拓宽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，并在材料科学和设备技术的新兴领域对他们进行培训，这些领域的基本见解可以带来深刻而快速的实际进步。在这个项目中的代表性不足的本科生的参与将通过正在进行的NSF资助的REU和LSAMP计划，麦克奈尔奖学金计划，并在PSU的本科生研究和指导计划的杠杆作用。该提案旨在设计和制造的新型混合扩散漂移自旋阀（HDDSV）阵列通过适应工业的过程。所提出的设备将允许石墨烯自旋输运参数，包括自旋寿命，自旋扩散长度和极化注入效率的变化的设备组件和尺寸的系统调查。采用非局域自旋阀（NLSV）装置研究石墨烯自旋输运，实验值比理论预测值低几个数量级。所提出的HDDSV被独特地设计为检测源自自旋极化电荷载流子的自旋累积的非本地信号，所述自旋极化电荷载流子远离铁磁（FM）/隧道势垒（TB）/石墨烯界面的影响而发生。这项研究工作代表了结合石墨烯合成，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。新的器件配置将具有将铁磁接触的影响与石墨烯自旋输运测量隔离的能力，同时能够同时进行自旋和电荷载流子操纵。该装置将允许新的自旋转移现象进行检查。对这种新型器件的研究将揭示铁磁接触和载流子漂移对石墨烯传输通道中自旋扩散长度和自旋寿命的基本影响。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.