ACT/SGER: Evaluation of a Novel Approach for Improved Growth of CdZnTe

ACT/SGER：改进 CdZnTe 生长的新方法的评估

• 批准号: 0345183
• 负责人: Jeffrey Derby
• 金额: $ 9.93万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345183&HistoricalAwards=false
• 关键词: ACT; SGER; Evaluation; Novel; Approach

This project addresses crystal growth of CdZnTe, a material useful as a portable, low-cost, and sensitive means to monitor radioactive materials via the detection of emitted gamma rays. There are several technologies for gamma detectors, such as classical sodium iodide (NaI) scintillation devices and liquid-nitrogen-cooled Germanium detectors. However, gamma detectors based on cadmium zinc telluride (CdZnTe) offer unique advantages: 1. CdZnTe operates as a direct detector, thereby allowing for the design of small detection probes and portable devices. 2. CdZnTe devices work at room temperature, thus avoiding cooling technology. 3. Since CdZnTe detectors have a much better resolution compared to NaI detectors, they are the only room temperature detectors that allow hand-held and portable devices to provide a detection of radioactive signatures behind significant lead or steel shieldings. Low cost, large-area, single crystals with low compositional variation and homogeneous electrical properties are sought. Currently, the growth of large, single crystals of CdZnTe is accomplished by the Bridgman method and is notoriously difficult. These crystals typically exhibit rather poor crystalline perfection, significant concentrations of large defects, and poor uniformity of Zn concentration. The objective of this project is to apply large-scale numerical simulation to assess an alternative growth configuration for CdZnTe - a destabilizing vertical Bridgman configuration rather than the classical stabilizing configuration. While counter intuitive and exploratory, this new growth technique may allow for dramatic improvements in CdZnTe substrate quality and process yields, and provides new understanding of bulk crystal growth processes. %%% The project addresses fundamental research issues associated with electronic/photonic materials having technological relevance. An important feature of the project is education and training, with emphasis on integration of research and education. The project aids in the development of the scientific workforce by exposing students to technical issues important for the security of the nation. Other broader impacts include relevance to the ACT program and potential advances in nuclear medical imaging devices, digital radiography, and high-resolution astrophysical imaging. Additionally, the understanding learned form this project will be applicable to the growth of other crystalline materials via the Bridgman method. This award is supported jointly by the NSF and the Intelligence Community. The Approaches to Combat Terrorism (ACT) Program in the Directorate for Mathematics and Physical Sciences supports new concepts in basic research and workforce development with the potential to contribute to national security.

该项目介绍了CDZNTE的晶体生长，这是一种可作为便携式，低成本和敏感方法来监测放射性材料的材料，可通过检测发射的伽马射线来监测放射性材料。有几种用于伽马探测器的技术，例如经典的碘化钠（NAI）闪烁设备和液氮冷却锗探测器。然而，基于镉的牙脲（CDZNTE）的伽马探测器提供了独特的优势：1。CDZNTE作为直接检测器运行，从而允许设计小检测探针和便携式设备。 2。CDZNTE设备在室温下工作，从而避免冷却技术。 3。由于与NAI探测器相比，CDZNTE探测器的分辨率要好得多，因此它们是唯一允许手持式和便携式设备提供可检测放射性签名的室温探测器，可在明显的铅或钢屏蔽背后进行放射性签名。寻找低成本，大面积，具有低组成变化和均匀电性能的单晶。当前，CDZNTE的大型单晶的生长是通过Bridgman方法实现的，众所周知。这些晶体通常表现出相当差的晶体完美，明显的大缺陷浓度和锌浓度均匀的均匀性。该项目的目的是应用大规模的数值模拟来评估CDZNTE的替代增长配置 - 一种不稳定的垂直Bridgman配置，而不是经典的稳定配置。虽然反直观和探索性，但这种新的增长技术可以允许CDZNTE底物质量和过程产量的显着改善，并提供对散装晶体生长过程的新了解。 %%％该项目解决了与具有技术相关性的电子/光子材料相关的基本研究问题。该项目的一个重要特征是教育和培训，重点是研究和教育的整合。该项目通过使学生面临对国家安全重要的技术问题来帮助发展科学劳动力的发展。其他更广泛的影响包括与ACT计划的相关性以及核医学成像设备，数字X线摄影和高分辨率天体物理成像的潜在进步。此外，该项目的理解形式将适用于通过Bridgman方法的其他结晶材料的生长。该奖项由NSF和情报界共同支持。数学和物理科学局中打击恐怖主义计划（ACT）计划的方法支持基础研究和劳动力发展中的新概念，有可能为国家安全做出贡献。