Quantitative electric field mapping of a p-n junction by DPC STEM

Satoko Toyama; Takehito Seki; Satoshi Anada; Hirokazu Sasaki; Kazuo Yamamoto; Yuichi Ikuhara; Naoya Shibata

doi:10.1016/j.ultramic.2020.113033

Quantitative electric field mapping of a p-n junction by DPC STEM

Ultramicroscopy. 2020 Sep:216:113033. doi: 10.1016/j.ultramic.2020.113033. Epub 2020 May 30.

Authors

Satoko Toyama¹, Takehito Seki¹, Satoshi Anada², Hirokazu Sasaki³, Kazuo Yamamoto², Yuichi Ikuhara⁴, Naoya Shibata⁵

Affiliations

¹ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
² Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan.
³ Advanced Technologies R&D Laboratories, Furukawa Electric Co., Ltd., Yokohama 220-0073, Japan.
⁴ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan.
⁵ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan. Electronic address: shibata@sigma.t.u-tokyo.ac.jp.

PMID: 32570133
DOI: 10.1016/j.ultramic.2020.113033

Abstract

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.