Laser-assisted atom probe tomography of oxide materials

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Atom probe tomography (APT) offers exceptional chemical analysis resolution for nanostructured materials.
• Traditional APT is limited to conductive materials due to field evaporation triggered by high-voltage pulses.
• Insulating materials like oxides have been largely inaccessible to APT analysis.

Purpose of the Study:

• To overcome the conductivity limitation of atom probe tomography.
• To demonstrate the applicability of APT to insulating oxide layers (NiO and WO3).
• To investigate the use of ultrashort laser pulses for field evaporation in APT.

Main Methods:

• Utilized atom probe tomography with 500 picosecond (ps) duration laser pulses for field evaporation.
• Analyzed thick Nickel Oxide (NiO) and Tungsten Trioxide (WO3) layers.
• Performed detailed mass spectrometry and lattice plane reconstruction.

Main Results:

• Successfully performed chemical analysis on insulating NiO and WO3 oxide layers using laser-pulsed APT.
• Mass spectra analysis confirmed that the measured stoichiometries accurately reflect the material composition.
• Lattice plane reconstruction indicated negligible surface diffusion, even with thermal pulses from the laser.

Conclusions:

• Ultrashort laser pulses enable atom probe tomography analysis of insulating oxide materials.
• This technique accurately determines the chemical composition and structure of previously inaccessible materials.
• The method overcomes a significant limitation in nanoscale chemical analysis, broadening APT's application scope.