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

电子学以操纵电子和其他载流子为基础。除了电荷之外，电子还具有可以被磁场和电场操纵的自旋，从而产生自旋极化电流，这种电流比单独电荷携带更多的信息。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。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）连接，已经实现了石墨烯中自旋输运的各种实验证明。然而，实验结果仍远低于理论预测值。为了弥补这一差距，提出了两个研究领域：石墨烯的制造和一种新型器件的设计，以推进基于石墨烯的自旋电子器件，该器件将具有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的转移。它还将扩大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培养他们，在这些领域，基本的见解可以带来深刻而快速的实际进步。本项目中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以及PSU的本科生研究和指导计划来加以利用。本课题旨在设计和制造一种新型的混合扩散漂移自旋阀（HDDSV）阵列，使其具有工业适应性。该装置将允许系统地研究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，这些参数是通过器件组件和尺寸的变化来实现的。采用非局部自旋阀（NLSV）装置研究石墨烯自旋输运的实验值比理论预测值低了几个数量级。所提出的HDDSVs设计独特，可检测自旋极化载流子自旋积累产生的非局部信号，这种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。这项研究代表了将石墨烯合成、器件制造、数据测量和分析相结合的多学科方法，以促进对石墨烯自旋输运性质的理解。本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。这种新颖的器件结构将能够隔离铁磁接触对石墨烯自旋输运测量的影响，同时实现自旋和电荷载流子的同时操作。所提出的装置将允许对新的自旋转移现象进行检验。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输运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.