Quantification of surface displacements and electromechanical phenomena via dynamic atomic force microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• Atomic Force Microscopy (AFM) techniques, including piezoresponse force microscopy (PFM), can detect nanoscale surface displacements.
• Current methods achieve sensitivities of approximately 1-3 picometers (pm) for surface displacement detection.
• Accurate quantification of these displacements is crucial for understanding material properties and phenomena.

Purpose of the Study:

• To develop a guideline for accurately quantifying picometer-scale surface displacements using AFM.
• To enhance the precision of contact resonance-enhanced AFM techniques.
• To minimize measurement artifacts and erroneous data interpretation in scanning probe microscopy.

Main Methods:

• Development of an analytical model for AFM cantilever vibrations.
• Incorporation of cantilever shape and tip-sample contact stiffness into the model.
• Experimental verification of the developed guideline, particularly for piezoresponse force microscopy (PFM).

Main Results:

• A guideline for accurate quantification of surface displacements at the picometer scale was demonstrated.
• The method accounts for cantilever geometry and contact stiffness at the first resonant mode.
• Experimental validation using ferroelectric materials confirmed the approach's efficacy for PFM.

Conclusions:

• The study presents a method for precise pm-scale surface displacement measurements with nanometer resolution.
• This approach is applicable to all cantilever-resonance-based scanning probe microscopy (SPM) techniques.
• The findings facilitate accurate measurements of piezoelectric constants and prevent data misinterpretation.