Giant Impedance Transition in Lanthanum Hexaboride (LaB6) Thin Films

六硼化镧 (LaB6) 薄膜中的巨阻抗转变

• 批准号: 9460511
• 负责人: Robert Tuffias
• 金额: $ 6.5万
• 依托单位: ULTRAMET, INC.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 1995-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9460511&HistoricalAwards=false
• 关键词: Giant; Impedance; Transition; Lanthanum; Hexaboride

This SBIR Phase I project will investigate a new phenomenon discovered recently at Ultramet while fabricating thermionic emission devices using thin films of lanthanum hexaboride (LaB6), a low work function thermionic emitter. This phenomenon, designated giant impedance transition (GIT), is represented by a large and very fast change in impedance (or resistance in DC) in response to external electromagnetic and electrostatic radiation. It should be noted that all observations of the GIT phenomenon have been extremely preliminary, obtained merely as a byproduct of the thermionic emission work being performed, with no focus having been given to the phenomenon itself. As such, much additional work is required to understand the physics of the GIT phenomenon and quantify it before proceeding to the device design stage. In this program, Ultramet will investigate the GIT phenomenon to achieve an understanding of its physics, perform quantitative analysis, and relate the behavior of the impedance change in the LaB6 deposit to its microstructure and thus, the processing technique. Ultramet will team with the Electrical Engineering Department of the University of Utah for characterization of the electrical and optical properties of LaB6 thin films produced at Ultramet. The successful completion of this effort will result in an understanding and quantification of the GIT phenomenon, as well as a direction for device design and fabrication to be pursued in follow-on work.

该SBIR第一阶段项目将研究Ultramet最近在使用六硼化镧（LaB6）薄膜制造电子发射器件时发现的一种新现象，LaB6是一种低功函数电子发射体。这种现象称为巨阻抗转变（GIT），其表现为响应于外部电磁辐射和静电辐射的阻抗（或直流电阻）的大且非常快的变化。应该注意的是，所有对GIT现象的观察都是非常初步的，仅仅是作为正在进行的电子发射工作的副产品获得的，没有关注现象本身。因此，在进入器件设计阶段之前，需要更多的工作来理解GIT现象的物理特性并对其进行量化。在该计划中，Ultramet将研究GIT现象，以了解其物理特性，进行定量分析，并将LaB6存款中的阻抗变化行为与其微观结构以及加工技术联系起来。Ultramet将与犹他州大学电气工程系合作，对Ultramet生产的LaB6薄膜的电气和光学特性进行表征。这项工作的成功完成将导致GIT现象的理解和量化，以及在后续工作中追求的器件设计和制造的方向。