Detector non-uniformity in scanning transmission electron microscopy

Area of Science:

• Materials Science
• Physics
• Electron Microscopy

Background:

• Annular detectors in scanning transmission electron microscopy (STEM) are crucial for imaging.
• Experimental evidence shows non-uniform detector responses, which are often ignored in simulations.
• This discrepancy can affect the accuracy of quantitative microscopy data.

Purpose of the Study:

• To investigate the impact of detector non-uniformity on STEM simulations.
• To quantify the scale of errors introduced by neglecting detector response.
• To propose methods for incorporating detector characterization into simulations.

Main Methods:

• Utilizing case study simulations of STEM.
• Analyzing discrepancies arising from non-uniform detector responses.
• Evaluating contrast errors at varying camera lengths and detector positions.

Main Results:

• Non-uniform detector response can lead to contrast errors of approximately 10% in STEM simulations.
• These errors are most significant when detectors are placed within or near the bright-field region at long camera lengths.
• The magnitude of error is sufficient to be non-trivial for quantitative analyses.

Conclusions:

• Accurate quantitative STEM analysis requires accounting for annular detector non-uniformity.
• Detector response normalization can be incorporated into simulations for improved accuracy.
• Future simulations should consider experimental detector characteristics for reliable results.