Contamination and the quantitative exploitation of EELS low-loss experiments

Area of Science:

• Materials Science
• Spectroscopy
• Electron Microscopy

Background:

• Quantitative analysis of low-loss electron energy loss spectra (EELS) relies on accurate signal intensity profiles.
• Sample contamination in electron microscopes can introduce artifacts, leading to erroneous EELS signals.
• Understanding contamination effects is crucial for reliable EELS data interpretation.

Purpose of the Study:

• To investigate the impact of carbonaceous contamination on low-loss EELS signals.
• To develop and validate a method for correcting contamination-induced artifacts.
• To estimate the errors in optical property determination caused by contamination.

Main Methods:

• Demonstration of spurious signal addition due to carbonaceous contamination on Si, HOPG, and SrTiO3.
• Characterization of the linear relationship between contamination rate and time.
• Implementation of a signal subtraction method to correct for contamination.

Main Results:

• Carbonaceous contamination introduces a distinct spurious signal in low-loss EELS.
• The contamination rate exhibits a linear dependence on time.
• A subtraction method effectively corrects for contamination, reducing errors.

Conclusions:

• Accurate EELS analysis requires addressing contamination effects.
• The proposed subtraction method provides a reliable way to correct for carbonaceous contamination.
• This correction is vital for precise determination of material optical properties, as shown for SrTiO3.