Dopant Site Occupancy Determined by Core-Loss-Filtered, Position-Averaged Convergent Beam Electron Diffraction

Area of Science:

• Materials Science
• Solid-State Physics
• Electron Microscopy

Background:

• Convergent beam electron diffraction (CBED) and its probe position-averaged variant (PACBED) are established techniques for analyzing crystal structure.
• PACBED patterns are effective for determining specimen thickness and crystal tilt.
• Quantifying dopant site occupancy typically requires techniques like X-ray spectroscopy.

Purpose of the Study:

• To demonstrate the utility of core-loss-filtered PACBED patterns for measuring dopant site occupancy.
• To adapt strategies from energy dispersive X-ray spectroscopy for electron diffraction analysis.
• To overcome quantification challenges using simulations.

Main Methods:

• Simulating core-loss-filtered PACBED patterns.
• Applying reciprocity principles between scanning and conventional transmission electron microscopy.
• Interpreting diffraction patterns using a modified Cliff-Lorimer approach.

Main Results:

• Core-loss-filtered PACBED patterns can determine the site occupancy of dopants in known crystal structures.
• A measurement-based quantification strategy is limited by elemental interaction ranges.
• Comparison with simulations incorporating generalized Cliff-Lorimer k-factors overcomes quantification limitations.

Conclusions:

• Core-loss-filtered PACBED is a viable method for site-specific dopant analysis.
• Simulations are crucial for accurate quantification when elemental interaction differences exist.
• This technique enhances the capabilities of transmission electron microscopy for materials characterization.