Visualization of electric fields using electron scattering

使用电子散射可视化电场

• 批准号: 2737047
• 金额: --
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2737047
• 关键词: Visualization; electric; fields; using; electron

Aberration-corrected Annular Dark Field STEM (ac-ADF-STEM) has provided some beautiful images and valuable insights into materials such as semiconductors, with each atom clearly resolved. New developments in fast pixelated detectors now allow a four-dimensional (4D) dataset to be acquired, where for each position of the electron probe, scanned in a 2D raster over the sample, a 2D image of the diffraction plane is recorded. This 4D-STEM data is useful because scientifically interesting signals, such as the presence of an internal electric field, exist in electron scattering patterns as second-order effects that are missed by an averaging detector but are very accessible when the complete data are collected. An electric field changes the trajectory of the electron beam due to the Lorentz force. The deflection of the electron beam is magnified by post-specimen lenses. The ability of 4D-STEM to measure internal fields in a device structure without the need for contacts is extremely useful and could be applied for example to measure the electric field in advanced functional materials. The capability in hardware, software and methods that will be developed will allow live imaging of internal electric fields at length scales from microns to atomic resolution.

像差校正的环形暗场STEM（ac-ADF-STEM）提供了一些美丽的图像和对半导体等材料的宝贵见解，每个原子都清晰可见。快速像素化检测器的新发展现在允许采集四维（4D）数据集，其中对于在样品上的2D光栅中扫描的电子探针的每个位置，记录衍射平面的2D图像。这种4D-STEM数据是有用的，因为科学上有趣的信号，如内部电场的存在，存在于电子散射模式中作为二阶效应，这些效应被平均检测器错过，但在收集完整数据时非常容易获得。电场由于洛伦兹力而改变电子束的轨迹。电子束的偏转被样品后透镜放大。4D-STEM无需接触即可测量器件结构中的内部场的能力非常有用，例如可用于测量先进功能材料中的电场。将开发的硬件、软件和方法的能力将允许在从微米到原子分辨率的长度尺度上对内部电场进行实时成像。