Conductive transparent fiber probes for shear-force atomic force microscopes

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Shear-force atomic force microscopy (SF-AFM) is crucial for nanoscale surface analysis.
• Analyzing partially insulating regions with traditional methods like scanning tunneling microscopy (STM) is challenging.
• There is a need for advanced probes capable of electrical measurements on diverse material compositions.

Purpose of the Study:

• To develop novel conductive transparent (CT) probes for SF-AFM.
• To enable nanoscale current injection and light collection from partially insulating samples.
• To expand the applicability of probe-current-induced luminescence measurements.

Main Methods:

• Fabrication of CT probes using elastic silica fibers with tapered, indium-tin-oxide coated tips.
• Coaxial nickel plating on silica fibers to achieve desired elasticity and conductivity.
• Optimization of nickel plating thickness (0.5-15 microm) for low resistance and smooth shear-force feedback.
• Acquisition of SF-AFM and current images on samples with mixed conductive and isolative regions.

Main Results:

• Successfully developed CT probes with nanometer-scale apex radius.
• Demonstrated effective current injection and light collection from nanometer-sized regions.
• Achieved low electrical resistance and smooth shear-force feedback through optimized nickel plating.
• Obtained clear SF-AFM and current images for samples containing both conductive and isolative areas.

Conclusions:

• CT probes significantly enhance SF-AFM capabilities for analyzing heterogeneous samples.
• These probes overcome limitations of STM for highly resistive and insulating materials.
• The developed CT probes open new avenues for nanoscale electrical and optical characterization.