SPIN ELECTRONICS: Varied Synthetic Approaches to the Development of Room-Temperature Ferromagnetic and Semiconducting Oxide Nanostructures for Silicon Based Spintronics

这项提案是为了响应21世纪的自旋电子学倡议，计划征集NSF 02-036而收到的。该计划的重点是用于自旋电子应用的钴掺杂过渡金属氧化物纳米结构的合成、表征和优化。这项工作是基于我们最近展示的Co掺杂锐钛矿型薄膜在室温下的铁磁性和半导体行为。这项研究将建立各种物理和化学合成方法制备的铁磁性半导体CoxTi-1-X02的结构、光学、电子和磁性之间的相互关系，这些合成方法包括氧等离子体辅助分子束外延、反应离子束溅射和基于溶液的水热、溶胶-凝胶法和水相共沉淀法。不同的合成路线应该导致不同的形貌和维度，包括单晶膜(2D)、纳米颗粒(OD)和纳米结构的平面阵列。在从实验室扩展到商业运营方面，它们的预后和成本也不同。这些材料的自旋相关输运和磁性行为将作为维度和结构的函数进行研究。对薄膜能带结构的详细评估，结合涉及钛酸锶缓冲层的专利技术，将用于在硅衬底上集成这些薄膜。最终目标不仅是在纳米尺度上设计这些材料，而且还将开发一套广泛的标准，作为探索其他掺杂氧化物在自旋电子学应用中的可行性的框架。最后，该项目有一个广泛的教育部分，将为在威斯康星州大学校园参与纳米技术IGERT计划的研究生的研究经验和培训增加新的维度。该计划由国家科学基金会工程局的土木和机械系统、化学和运输系统以及电气和通信系统部门共同资助。

This proposal was received in response to the Spin Electronics for the 21st century Initiative, Program Solicitation NSF 02-036. The proposal focuses on the synthesis, characterization and optimization of Cobalt-doped transition metal oxide nanostructures for spin-electronics applications. The proposed work is based on our recent demonstration of robust ferromagnetic and semiconducting behavior at room temperature in Co-doped anatase thin films. The proposed research will establish interrelationships among the structural, optical, electronic, and magnetic properties of ferromagnetic, semiconducting CoxTi-1-x02 fabricated by a variety of physical and chemical synthesis routes, including oxygen plasma assisted molecular beam epitaxy, reactive ion-beam sputter deposition, and solution-based hydrothermal, sol-gel, and aqueous co-precipitation methods. Different synthetic routes should lead to different morphologies and dimensionalities, including single-crystal films (2D), nanoparticles (OD), and planar arrays of nanostructures. They also have different prognoses and costs for scaling from laboratory to commercial operation. Spin-dependent transport and magnetic behavior of these materials as a function of dimensionality and structure will be investigated. Detailed evaluation of the band structure of the films, combined with proprietary technology involving SrTiO3 buffer layers, will be used to integrate these films on silicon substrates. The ultimate goal will not only be to engineer these materials at the nanometer length scales, but to develop a broad set of criteria that will serve as the framework to explore the viability of other doped-oxides for spintronics applications. Finally, the project has a broad education component that will add new dimensions to the research experience and training of graduate students participating in the nanotechnology IGERT program on the UW campus.This proposal is being co-funded by the Divisions of Civil and Mechanical Systems, Chemical and Transport Systems and Electrical and Communication Systems in the Directorate of Engineering of the National Science Foundation.