CAREER: Atomic Processes in Low Temperature Molecular Beam Epitaxy of Diluted Magnetic III/V Compound Semiconductors

该职业项目专注于稀磁III/V化合物半导体的合成。这些材料有望用于下一代电子-自旋电子学，在自旋电子学中，电子的自旋和电荷属性都具有功能。这是一个重大的材料科学挑战，因为在主体半导体中掺入高浓度的磁性离子会导致相分离和材料完整性的破坏。克服这一困难的途径是利用低温分子束外延。采用外延生长、原位测量和非原位测量相结合的方法，研究外延生长过程中发生的原子尺度过程与薄膜的电/磁性能之间的直接关系。将研究两种候选材料系统，GaMnAs和GaMnN。采用分子束外延技术生长外延薄膜，利用变温扫描隧道显微镜(STM)、反射高能电子衍射仪和横截面扫描隧道显微镜(STM)直接原位、原子尺度地表征薄膜的物理性质。同时，结构、电和磁特性将通过非原位技术来确定，如透射电子显微镜、高分辨率x射线衍射和磁输运测量。然后建立了稀磁III/V化合物半导体的低温生长模型。这可能有助于创造新的制造方法，与现有的化合物半导体工艺兼容。该项目还强调加强本科生和研究生的教育经验。为自旋电子学的一个新的焦点领域提出了实质性的课程开发。特别是，将开发有关纳米尺度凝聚物质的概念和技术的课程。对学生教育的责任感也有助于帮助他们找到一份可以利用他们在学校获得的技能和知识的职业。将在工业和教育外展方面提出新的倡议。在SPE方面，将成立一个产业咨询和职业委员会，以帮助为学生培养与产业相关的活动和机会，包括实习和工业研究经验。这个项目的教育成果有望将新的概念和技术带到课堂上，并为学生提供未来在工业中就业的绝佳机会。%该项目解决具有高度技术相关性的材料科学主题领域的基础研究问题。该项目的范围将使学生在材料合成、加工和表征方面面临挑战。该项目的一个重要特点是高度重视教育，并将研究与教育相结合。***

This CAREER project focuses on synthesis of dilute magnetic III/V compound semiconductors. These materials are expected to be used in next generation electronics-spintronics, where both the spin and charge properties of electrons perform functionality. This represents a major materi-als science challenge because incorporation of high concentrations of magnetic ions in host semi-conductors causes phase separation and destruction of material integrity. The approach to over-come this difficulty is utilization of low temperature molecular beam epitaxy. Using a combina-tion of epitaxial growth, in-situ and ex-situ measurements, direct correlation between atomic scale processes occurring during epitaxial growth and electronic/magnetic properties of the films will be investigated. Two candidate material systems, GaMnAs and GaMnN, will be examined. Epitaxial thin films will be grown by molecular beam epitaxy, and their physical properties di-rectly characterized in situ with atomic-scale precision by variable-temperature scanning tunnel-ing microscopy (STM), reflection high-energy electron diffraction and cross-sectional STM. In conjunction, structural, electrical and magnetic characteristics will be determined by ex situ tech-niques such as transmission electron microscopy, high-resolution x-ray diffraction, and magneto-transport measurement. A model of low temperature growth of diluted magnetic III/V compound semiconductors will then be developed. This may help to create new manufacturing methods that are compatible with existing compound semiconductor processing.This project also emphasizes the enhancement of educational experiences for students at both undergraduate and graduate levels. Substantial curriculum development for a new focus area in spintronics is proposed. Particularly, courses on the concepts and techniques of condensed matter at nanoscale will be developed. A sense of commitment to the education of the students also ex-tends to assisting them in finding a career where they can utilize their skills and knowledge ac-quired in school. New initiatives in industrial and educational outreach will be instituted. Spe-cifically, an industrial advisory and career committee will be formed to help foster industrially relevant activities and opportunities for students including internship and industrial research ex-periences. Outcomes of the educational effort of this project are expected to bring new concepts and techniques into the classroom and outstanding opportunities for students for future employ-ment in industry.%%% The project addresses fundamental research issues in a topical area of materials science having high technological relevance. The scope of the project will expose students to challenges in materials synthesis, processing, and characterization. An important feature of the project is the strong emphasis on education, and the integration of research and education. ***