Unattended Analysis of Multiple Insulating Samples

Significance of the Topic

The unattended analysis of insulating samples by X-ray photoelectron spectroscopy (XPS) enables laboratories to maximize instrument utilization by running complex sequences overnight and during weekends without operator intervention. This capability is essential for high-throughput surface analysis of diverse materials in research and industrial environments.

Objectives and Study Overview

This study showcases the Thermo Scientific Theta Probe XPS system’s ability to perform unattended analyses on multiple insulating samples. It details the configuration of sample holders, the definition of complex measurement sequences, and the evaluation of performance across different sample types and measurement modes.

Instrumentation Used

• Thermo Scientific Theta Probe XPS spectrometer
• Avantage data system with experiment tree structure
• Microfocusing monochromator
• Charge compensation system
• Precision X–Y–Z sample stage with optical microscope
• Ion gun for sputter cleaning and depth profiling

Methodology

Samples including PTFE, mica, smooth polymers, and fibers were mounted on a multi-sample holder and positioned with micron resolution. An experiment tree defined in the Avantage software controlled X-ray source parameters, stage movements, charge compensation, spectral acquisitions at various spot sizes (20–400 µm), line scans, and chemical state mapping using snapshot mode.

Main Results and Discussion

• PTFE spectra showed consistent C 1s and F 1s peak shapes across spot sizes, with minimal broadening at smaller spots.
• Line scans on a polymer fiber over 1.7 mm demonstrated precise stage positioning and stable charge compensation, yielding uniform C 1s, O 1s, N 1s, and Si 2p signals.
• Chemical state mapping of ink on PET using 20×20 snapshots resolved distinct C 1s and O 1s components via Target Factor Analysis and non-linear least squares fitting, clearly differentiating ink and substrate regions.

Benefits and Practical Applications

Unattended operation optimizes instrument uptime and throughput. Automated control of charge compensation and spot size transitions eliminates manual adjustments, ensuring reproducible results. The system supports diverse analyses including small-area measurements, line scans, depth profiling, and large-area mapping for QA/QC, materials research, and industrial surface analysis.

Future Trends and Opportunities

Advancements may include integration of machine learning for dynamic experiment optimization, enhanced remote monitoring, expansion of automated sample libraries, and improved data analytics workflows. These developments will further streamline XPS operations and extend applications into new fields.

Conclusion

The Thermo Scientific Theta Probe coupled with the Avantage data system delivers robust unattended XPS analysis of insulating materials, combining precision positioning, reliable charge compensation, and versatile experiment control to boost laboratory efficiency and data quality.

References

• Thermo Fisher Scientific. Application Note AN31022: Charge Compensation Method.
• Thermo Fisher Scientific. Application Note AN31005: Avantage Data System.
• Thermo Fisher Scientific. Application Note AN31009: Snapshot Acquisition.
• Thermo Fisher Scientific. Application Note AN31067: Unattended Analysis of Multiple Insulating Samples.