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Quantitative electric field mapping of a p-n junction by DPC STEM
Satoko Toyama1, Takehito Seki1, Satoshi Anada2
1Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
Ultramicroscopy
|June 23, 2020
Summary
This study introduces a new method to accurately measure electromagnetic fields in thick specimens using differential phase contrast (DPC) imaging. The technique corrects for inelastic scattering, improving the reliability of scanning transmission electron microscopy (STEM) field quantification.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Electron Microscopy
Background:
- Differential Phase Contrast (DPC) imaging in Scanning Transmission Electron Microscopy (STEM) measures local electromagnetic fields at high spatial resolution.
- Traditional DPC quantification methods involve analyzing diffraction patterns or using Phase Contrast Transfer Function (PCTF) deconvolution.
- Previous methods significantly underestimate field strength in thick specimens due to inelastic scattering, primarily bulk plasmon scattering.
Purpose of the Study:
- To develop an improved method for quantifying electromagnetic fields using DPC imaging in STEM.
- To address the underestimation of field strength caused by inelastic scattering in thick specimens.
- To enhance the accuracy of DPC measurements by modifying the PCTF deconvolution approach.
Main Methods:
- A modified PCTF deconvolution method was developed to remove the effects of inelastic scattering from segmented detector DPC signals.
- The new technique was applied to measure electromagnetic fields in thick specimens.
- Results were compared with those obtained from pixelated detector DPC and electron holography.
Main Results:
- The developed method effectively removes the influence of inelastic scattering on DPC signals.
- Field quantification using the modified PCTF deconvolution showed good agreement with pixelated detector DPC.
- Measurements obtained with the new technique were consistent with electron holography results within an acceptable error margin.
Conclusions:
- The novel method accurately quantifies electromagnetic fields in thick specimens by correcting for inelastic scattering.
- This advancement improves the reliability and accuracy of DPC imaging in STEM for materials analysis.
- The findings validate the modified PCTF deconvolution approach for precise electromagnetic field mapping.
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