Quantification of in-contact probe-sample electrostatic forces with dynamic atomic force microscopy.

Area of Science:

• Surface science
• Nanotechnology
• Atomic force microscopy

Background:

• Atomic force microscopy (AFM) uses resonant cantilever vibrations for high-sensitivity surface displacement detection.
• Existing AFM modes leverage this sensitivity for imaging.
• Quantifying electrostatic forces in the probe-sample junction remains a challenge.

Purpose of the Study:

• To demonstrate a cantilever-resonance-based method for quantifying electrostatic forces in the probe-sample junction.
• To measure electric field strength at the AFM probe tip apex.
• To understand the influence of these fields on material properties.

Main Methods:

• Utilizing cantilever resonance in atomic force microscopy to detect displacements caused by electrostatic forces.
• Applying surface potential or bias voltage to the AFM probe.
• Combining experimental measurements with modeling to determine electric field strength.

Main Results:

• Electrostatic forces produce signals equivalent to picometer-scale surface displacements.
• Electric field strength in the junction can reach approximately 1 V/nm at a few volts bias.
• Field strength is limited by non-ideal tip-sample contact.

Conclusions:

• The developed method quantifies electrostatic forces and electric fields in the AFM tip-sample junction.
• High electric fields can significantly influence material states and kinetic processes.
• This work provides a baseline for electromechanical AFM measurements and probing field-induced phenomena.