Structural and micromechanical analysis of ceramics and glass by Raman microprobe and cathodoluminescence spectroscopy.

本项目综述了近年来在陶瓷和玻璃材料/器件表面残余应力场的高空间分辨率表征方面取得的成就。测量基于压电光谱效应（即，由于叠加应力场的存在而发生的光波长偏移）。纳米尺度的应力评估可以独立于PL/CL发射背后的特定机制，通过利用拉曼微探针装置的上级深度分辨率和专门设计用于低电压测量的场发射枪扫描电子显微镜（FEG-SEM）的高横向分辨率来进行。自动扫描程序已经开发和扩展，以便在几乎真实的时间内收集和处理大量采集数据（每平方米多达10^6个数据点）。这种能力非常适合于陶瓷和玻璃器件表面残余应力的纳米级评估。通过这种技术（这里称为阴极发光压电光谱）实现的微机械信息在于一个显着较小的规模比光激发发光探测，可以被视为自然对应的化学元素映射常规操作到传统的SEM设备根据电子激发的X射线发射。在FEG-SEM中的实验纳米尺度机械评估可以在新型材料的微观结构设计中提供额外的自由度，并且还提供对于开发具有高效率和可靠性的新陶瓷和玻璃器件至关重要的可访问性。

Recent achievements in high spatial resolution characterization of residual stress fields stored near the surface of ceramic and glass materials/devices have been reviewed in this project. Measurements are based on the piezo-spectroscopic effect (i.e., the light wavelength shift occurring due to the presence of a superimposed stress field) observed for selected photoluminescence(PL) and cathodoluminescence(CL) bands of ceramic and glass materials. Nano-scale stress assessments can be performed, independent of the particular mechanism behind the PL/CL emission, by exploiting the superior in-depth resolution of the Raman microprobe device and the high lateral resolution of a field-emission-gun scanning electron microscopes(FEG-SEM) specially designed for low-voltage measurements. Automatic scanning routines have been developed and expanded in order to collect and to process in nearly real time a large number of acquisition data (up to 10^6 data point per □ m^2). This capability is well suited for the nano-scale assessment of residual stresses on the surface of ceramic and glass devices. The micromechanical information achieved by this technique (referred here to as cathodoluminescence piezo-spectroscopy) lies on a significantly smaller scale than that probed by photo-stimulated luminescence and can be regarded as the natural counterpart of chemical elemental mapping routinely operated into conventional SEM devices according to electron-stimulated X-ray emission. Experimental nano-scale mechanical assessments in the FEG-SEM may provide an additional degree of freedom in the microstructural design of novel materials and also the accessibility that is essential for developing new ceramic and glass devices with high efficiency and reliability.