Comparison of the quantitative analysis performance between pulsed voltage atom probe and pulsed laser atom probe

Area of Science:

• Materials Science
• Analytical Chemistry
• Surface Science

Background:

• Local Electrode Atom Probe (LEAP) is a powerful technique for nanoscale material analysis.
• Quantitative accuracy in atom probe tomography can be affected by experimental parameters like temperature and evaporation mode.
• Fe-Cu binary alloys serve as a model system to study solute behavior and evaporation dynamics.

Purpose of the Study:

• To compare the quantitative analysis performance of voltage-mode and laser-mode in a LEAP3000X HR.
• To investigate the influence of specimen temperature on the accuracy of Fe-Cu composition measurements.
• To determine the optimal mode for reliable quantitative analysis in atom probe tomography.

Main Methods:

• Utilized a Fe-Cu binary model alloy for experiments.
• Performed quantitative analysis using both voltage-mode and laser-mode on the Local Electrode Atom Probe (LEAP3000X HR).
• Varied specimen temperatures (e.g., 20K, 40K) to assess performance under different thermal conditions.

Main Results:

• Voltage-mode showed higher apparent Cu concentration than actual at <=40K due to iron detection loss, decreasing with temperature rise.
• Laser-mode consistently yielded apparent concentrations closer to actual values, never exceeding them even at 20K.
• Laser-mode demonstrated superior quantitative performance across a broad temperature range compared to voltage-mode.

Conclusions:

• Pulsed laser atom probe significantly enhances quantitative accuracy by mitigating detection loss and preferential evaporation.
• Laser-mode is the preferred method for precise quantitative analysis in atom probe tomography, especially for alloys with differing evaporation fields.
• The findings provide crucial insights for optimizing experimental parameters in LEAP analysis for reliable material characterization.