Exploring local electrostatic effects with scanning probe microscopy: implications for piezoresponse force microscopy...

Area of Science:

• Surface Science
• Nanotechnology
• Electrochemistry

Background:

• Contact mode Kelvin probe force microscopy (cKPFM) leverages electrostatic interactions between a tip and sample in physical contact.
• Traditional noncontact KPFM signals are influenced by sample dielectric and tip stiffness properties.

Purpose of the Study:

• To investigate the feasibility and advantages of using cKPFM for high-resolution surface potential measurements.
• To explore the relationship between tip-sample contact, electrostatic forces, and surface electrochemical phenomena.

Main Methods:

• Implementation of contact mode Kelvin probe force microscopy (cKPFM).
• Measurement of electrostatic forces and tip-surface capacitance variations under contact conditions.
• Analysis of bias-induced changes in junction potential and electromechanical responses.

Main Results:

• Electrostatic forces are measurable even with stiff tips (4.5 N/m) in contact mode.
• cKPFM provides higher lateral and temporal resolution compared to noncontact KPFM.
• Significant, reproducible tip-surface capacitance variations attributed to surface electrochemistry were observed.
• Surface charge states at zero bias and hysteretic electromechanical responses were detected on a nonferroelectric surface.

Conclusions:

• cKPFM is a viable technique for high-resolution surface potential and electrochemical studies.
• The observed phenomena have significant implications for understanding triboelectricity and piezoresponse force microscopy.
• Contact-induced electrostatic interactions offer unique insights into surface properties.