Interpreting nanovoids in atom probe tomography data for accurate local compositional measurements

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Accurate chemical composition analysis around nanovoids is crucial for materials research.
• Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) are key nanoscale characterization techniques.
• Understanding void imaging artifacts in APT is essential for reliable data interpretation.

Purpose of the Study:

• To investigate the impact of nanovoids on APT reconstructions.
• To elucidate the mechanisms behind local density variations near voids in APT data.
• To develop a robust method for quantifying chemical segregation around nanovoids.

Main Methods:

• Correlative imaging using APT and STEM.
• Simulated APT experiments to model void formation and evaporation.
• Development of a general approach for compositional analysis near voids.

Main Results:

• Nanovoids can cause both increases and decreases in local atomic density within APT reconstructions.
• Void ring structures and differing atomic evaporation fields dictate local density variations.
• The proposed method allows for more accurate compositional determination near voids compared to STEM.

Conclusions:

• The study clarifies APT void imaging artifacts and their impact on chemical composition quantification.
• A novel approach enhances the accuracy of chemical segregation analysis around nanovoids using APT.
• This work improves the reliability of APT for materials characterization at the nanoscale.