Local electromagnetic fields in a specimen is measured at high spatial resolutions using differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). According to previous studies, DPC signals can be quantified by measuring the center of mass of the diffraction pattern intensity and/or performing a deconvolution method based on a phase contrast transfer function (PCTF). However, when using a segmented detector, the field strength has been considerably underestimated for a very thick specimen. The main cause of the underestimation is assumed to be inelastic scattering, mainly bulk plasmon scattering. In this study, we develop a method to remove this inelastic scattering effect from segmented detector DPC signals by modifying the PCTF deconvolution method. Field quantification results using this new technique are compared with those using pixelated detector DPC and electron holography, and all results indicated good agreement within an error margin.

中文翻译：

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通过 DPC STEM 对 ap-n 结进行定量电场映射

使用扫描透射电子显微镜 (STEM) 中的微分相位对比 (DPC) 成像以高空间分辨率测量样品中的局部电磁场。根据之前的研究，DPC 信号可以通过测量衍射图案强度的质心和/或执行基于相衬传递函数 (PCTF) 的反卷积方法来量化。然而，当使用分段探测器时，对于非常厚的样品，场强被大大低估了。假设低估的主要原因是非弹性散射，主要是体等离子体散射。在这项研究中，我们开发了一种方法，通过修改 PCTF 解卷积方法，从分段检测器 DPC 信号中消除这种非弹性散射效应。