Optimization of NBED simulations for disc-detection measurements

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electron Microscopy

Background:

• Nano-beam electron diffraction (NBED) is crucial for analyzing lattice strain and polarization fields in advanced materials.
• Accurate NBED measurements depend on understanding specimen properties and electron optical parameters.
• Simulations are essential for predicting NBED pattern outcomes and validating experimental data.

Purpose of the Study:

• To investigate the precision, accuracy, and spatial resolution of NBED measurements.
• To develop accurate NBED simulations by incorporating experimental characteristics.
• To analyze the impact of specimen properties on NBED pattern analysis and potential misinterpretations.

Main Methods:

• Development of NBED pattern simulations incorporating background intensity, Poisson noise, inelastic scattering, and camera transfer quality.
• Focus on the detection of the central disc in crystalline silicon.
• Investigation of specimen property effects (strain, surface morphology, composition) on simulated NBED patterns.

Main Results:

• Simulations require accounting for experimental factors (noise, scattering, camera quality) for realistic NBED pattern prediction.
• Changes in surface morphology and chemical composition induce significant shifts (tens to hundreds of µrad) in the central disc.
• These shifts due to surface effects can be comparable to or larger than those caused by electric polarization fields (MV/cm).

Conclusions:

• Optimized NBED simulations provide reliable predictions for experimental analysis.
• Surface morphology and composition significantly influence NBED measurements, potentially leading to misinterpretation of strain or polarization.
• Careful consideration of experimental artifacts is vital for accurate NBED analysis of nanoscale materials.