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.

该项目致力于 CdZnTe 的晶体生长，这种材料可作为一种便携式、低成本、灵敏的手段，通过检测发射的伽马射线来监测放射性材料。伽马探测器有多种技术，例如经典的碘化钠 (NaI) 闪烁装置和液氮冷却锗探测器。然而，基于碲化镉锌 (CdZnTe) 的伽马探测器具有独特的优势： 1. CdZnTe 作为直接探测器运行，从而允许设计小型探测探头和便携式设备。 2. CdZnTe器件在室温下工作，从而避免了冷却技术。 3. 由于 CdZnTe 探测器比 NaI 探测器具有更高的分辨率，因此它们是唯一允许手持式和便携式设备检测重要铅或钢屏蔽后面的放射性特征的室温探测器。寻求具有低成分变化和均匀电性能的低成本、大面积单晶。目前，大型CdZnTe单晶的生长是通过布里奇曼法完成的，并且是出了名的困难。这些晶体通常表现出相当差的结晶完美性、大缺陷的显着集中以及锌浓度的均匀性差。该项目的目标是应用大规模数值模拟来评估 CdZnTe 的替代生长配置 - 不稳定的垂直布里奇曼配置而不是经典的稳定配置。虽然与直觉和探索性相反，但这种新的生长技术可能会显着提高 CdZnTe 衬底质量和工艺产量，并提供对块状晶体生长工艺的新理解。 %%% 该项目解决与具有技术相关性的电子/光子材料相关的基础研究问题。该项目的一个重要特点是教育培训，强调研究与教育的结合。该项目通过让学生接触对国家安全重要的技术问题来帮助科学队伍的发展。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、数字射线照相和高分辨率天体物理成像方面的潜在进展。此外，从该项目中学到的理解将适用于通过布里奇曼方法生长其他晶体材料。该奖项由美国国家科学基金会和情报界共同支持。数学和物理科学局的打击恐怖主义方法（ACT）计划支持基础研究和劳动力发展方面的新概念，有可能为国家安全做出贡献。