Large Scale Epitaxy of Mercury-Based High-Temperature Superconducting Thin Films in Cation-Exchange Process

阳离子交换过程中汞基高温超导薄膜的大规模外延

• 批准号: 9901460
• 负责人: Judy Wu
• 金额: $ 28.51万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9901460&HistoricalAwards=false
• 关键词: Large; Scale; Epitaxy; Mercury; Based

9901460WuThis project addresses the growth mechanism of thin films of Hg-based high-Tc superconductors (Hg-HTSs) in a novel cation exchange process, and aims at developing technologically feasible techniques for high-quality epitaxy of Hg-HTS thin films over large scales. The high volatility of the Hg-HTSs limits use of conventional thermal-reaction processing over large areas. The proposed research on the cation-exchange process addresses this problem in epitaxy of volatile compounds using an approach, in which a highly volatile compound is formed by replacing a weakly bonded cation in a precursor lattice with the desired volatile cation. The epitaxy of the volatile compound is directly inherited from the epitaxial precursor matrix. By choosing precursor matrices with pre-designed crystalline structures and chemical compositions, the cation-exchange process allows high-quality epitaxy of many existing volatile compounds as well as a search for new volatile compounds. Four topics to be addressed include: (1) Identification of characteristic parameters in the cation-exchange process and study of their effects on the cation-exchange mechanism; (2) Development of a three-zone cation exchange process for large-area epitaxy ( 2 inches in diameter); (3) Study of surface morphology and film/substrate-interface microstructures of cation-exchange processed Hg-HTS thin films on technologically compatible substrates; and (4) Direct conversion of Tl-HTS devices to Hg-HTS devices.%%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. The success of this research may lead to development of commercially viable technologies for Hg-HTS film-based applications including microwave components/systems, infrared detectors, and high-current superconducting tapes, and is expected to allow establishment of novel methods for synthesis of volatile compounds with pre-designed crystalline structures and chemical compositions. The research will contribute basic materials science knowledge at a fundamental level to new aspects of electronic devices. A variety of fundamental issues are to be addressed in these investigations, and the proposed experiments will also develop a technologically important superconducting material. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area.***

9901460Wu该项目研究了Hg基高温超导体（Hg-HTS）薄膜在新型阳离子交换过程中的生长机制，旨在开发技术上可行的大规模Hg-HTS薄膜高质量外延技术。 Hg-HTS 的高挥发性限制了传统热反应处理的大面积使用。所提出的关于阳离子交换过程的研究使用一种方法解决了挥发性化合物外延中的这个问题，其中通过用所需的挥发性阳离子取代前体晶格中的弱键合阳离子来形成高挥发性化合物。挥发性化合物的外延直接继承自外延前体基质。通过选择具有预先设计的晶体结构和化学成分的前体基质，阳离子交换过程可以实现许多现有挥发性化合物的高质量外延以及寻找新的挥发性化合物。四个课题包括：（1）阳离子交换过程中特征参数的识别及其对阳离子交换机制的影响研究； （2）开发大面积外延（直径2英寸）的三区阳离子交换工艺； (3) 在技术兼容的基底上进行阳离子交换处理的 Hg-HTS 薄膜的表面形貌和薄膜/基底界面微结构的研究； (4) 将 Tl-HTS 装置直接转换为 Hg-HTS 装置。%%%该项目解决具有高度潜在技术相关性的材料科学主题领域的基础研究问题。这项研究的成功可能会导致基于 Hg-HTS 薄膜应用的商业可行技术的开发，包括微波组件/系统、红外探测器和高电流超导带，并有望建立具有预先设计的晶体结构和化学成分的挥发性化合物合成的新方法。该研究将从根本上为电子设备的新方面贡献基础材料科学知识。这些研究将解决各种基本问题，拟议的实验还将开发一种技术上重要的超导材料。 该计划的一个重要特点是通过在基础和技术重要领域对学生进行培训，将研究和教育融为一体。***