Development of Scanning Photothermal Microscope for Nanoscale Sub-surface Structural Defect Characterization

开发用于纳米级次表面结构缺陷表征的扫描光热显微镜

• 批准号: 0926704
• 负责人: Xinwei Wang
• 金额: $ 26.88万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926704&HistoricalAwards=false
• 关键词: Development; Scanning; Photothermal; Microscope; Nanoscale

The objectives of this project are to conduct research on break-through sub-surface structural defect characterization based on laser-coupled scanning probe photothermal concept to achieve depth profiling with nanoscale spatial resolution. The proposed sub-surface characterization features nanoscale spatial resolution using frequency-modulated near-field laser focusing and thermal expansion sensing. Research will be carried out to study the physical phenomena in sub-surface characterization, including near-field laser focusing, nanoscale heating, thermal transport, and elastic surface displacement. A physical model will be developed for dynamic surface displacement under periodical nanoscale laser heating.Upon accomplishment, the proposed research will open a new compelling way for sub-surface structural defect characterization with nanoscale spatial resolution while most of the existing scanning probe technologies are for characterizing surface properties. The surface displacement sensing in the proposed characterization takes advantage of the atomic force acoustic mechanism and features fast response. By varying the modulation frequency of the laser beam incident on the scanning probe tip, we will be able to vary the characterization length and diagnose sub-surface defect of different depth. Furthermore, deliverables will include a comprehensive physical model to interpret the characterization data to obtain quantitative information about the size and depth of structural defect. The strong capability of the proposed sub-surface characterization will make it have broad applications in structural diagnostics of nanostructured materials and evaluation of sub-surface structure in nanoscale material processing. Results of the proposed research will be disseminated through broad publications. Furthermore, the research results will be integrated into new course development and conventional class teaching at Iowa State University. Extensive undergraduate participation via summer research will be arranged. Outreach services to K-12 students will be facilitated through the ESPP program of Iowa State University.

本项目的目标是进行基于激光耦合扫描探针光热概念的穿透次表面结构缺陷表征的研究，以实现具有纳米级空间分辨率的深度分析。拟议的子表面表征功能纳米级的空间分辨率，使用调频近场激光聚焦和热膨胀传感。将开展研究，以研究次表面表征中的物理现象，包括近场激光聚焦、纳米级加热、热传输和弹性表面位移。本研究将建立周期性纳米激光加热下表面动态位移的物理模型，为纳米尺度的亚表面结构缺陷表征开辟一条新的途径，而现有的扫描探针技术大多用于表征表面性质。表面位移传感在拟议的表征利用原子力声学机制和功能快速响应。通过改变入射到扫描探针尖端上的激光束的调制频率，我们将能够改变表征长度并诊断不同深度的亚表面缺陷。此外，可交付成果将包括一个全面的物理模型，用于解释表征数据，以获得有关结构缺陷大小和深度的定量信息。所提出的亚表面表征的强大能力将使其在纳米结构材料的结构诊断和纳米材料加工中的亚表面结构评估中具有广泛的应用。拟议研究的结果将通过广泛的出版物传播。此外，研究成果将被整合到新的课程开发和传统的课堂教学在爱荷华州州立大学。通过夏季研究将安排广泛的本科生参与。对K-12学生的外展服务将通过爱荷华州州立大学的ESPP项目提供便利。