Measuring material softening with nanoscale spatial resolution using heated silicon probes

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Local Thermal Analysis (LTA) traditionally lacked nanoscale resolution.
• Previous LTA methods used probes with resolutions around 10 micrometers.
• Investigating nanoscale features requires higher spatial resolution techniques.

Purpose of the Study:

• To demonstrate four methods for nanoscale LTA using heated silicon probes.
• To analyze the softening behavior of thin polystyrene films with high spatial resolution.
• To assess the capabilities of heated silicon probes for advanced thermal analysis.

Main Methods:

• Utilized heated silicon atomic force microscopy (AFM) probes.
• Performed local thermal analysis (LTA) on thin polystyrene films.
• Measured film softening behavior with 100 nm spatial resolution.

Main Results:

• Achieved 100 nm spatial resolution for LTA, a significant improvement over previous methods.
• Measured a polystyrene softening temperature of 120°C using nanoscale LTA.
• Observed a discrepancy with bulk ellipsometry (100°C), attributed to thermal contact resistance (10^7 K/W).

Conclusions:

• Heated silicon probes enable thermal analysis with nanoscale spatial resolution.
• The technique allows for bulk fabrication and parallelization for high-throughput analysis.
• Thermal contact resistance at the probe tip influences heat flow and limits technique precision.