报告题目：扫描电子衍射技术和它在材料表征中的应用
报 告 人：穆晓柯博士
报告时间：2019年1月8日 10：00
报告地点：磬苑校区现代实验技术中心A507
主办单位：物质科学与信息技术研究院
欢迎各位老师、同学届时前往！
科学技术处
2018年12月28日
报告摘要：
Scanning-/Transmission electron microscopy (S/TEM) offers sophisticated methods helping material scientists understand the microscopic structure of various interesting materials. Electron diffraction provides abundant structural information being one of the most traditional TEM methods. It brings together sensitive measures in d-spaces, crystal symmetry and orientation. Its intrinsic drawback is the lack of spatial resolution comparing to atomic resolved high resolution techniques (HR(S)TEM).
With increasing potential of electron detecting cameras, scanning diffraction (4DSTEM) in a modern STEM microscope becomes feasible. It records individual two dimensional (2D) diffraction patterns by 2D stepwise scanning a fine electron probe on the specimen. The 4D data array can be used to map the atomic structure and crystal orientation without compromising between the spatial resolution and large area specimens which is often highly demanded for statistical analysis. In addition, pair distribution function (PDF) analysis of the 4D diffraction data provides the possibility to map phases of (low-contrast) organic blends at low-dose conditions.
After a brief introduction of the methodology, this talk would like to show the power of 4DSTEM on solving real material questions. Examples will include phase mapping and interface orientation analysis of partially dis/charged battery, low-dose characterization of amorphous polymers for solar cell application, in-situ differential phase contrast (DPC) imaging of material inner mean potentials, such as for magnetic field measurements.