Exploring responsivity, sensitivity and resolution in amplitude modulated AFM: a study of global behavior and...

Area of Science:

• Atomic Force Microscopy (AFM)
• Surface Science
• Nanotechnology

Background:

• Conflicting definitions of sensitivity, resolution, and responsivity exist in AFM literature.
• A lack of comprehensive studies on how system and process parameters affect AFM sensitivity.

Purpose of the Study:

• To establish clear definitions for sensitivity, resolution, and responsivity within the context of AFM.
• To present a global analysis of AFM cantilever-sample system behavior concerning responsivity, noise, and sensitivity.
• To identify parameters that optimize AFM sensitivity.

Main Methods:

• Derivation of an analytical model for amplitude and phase as functions of tip-sample distance (small amplitudes).
• Scaling of analytical equations for generalized parameter influence analysis.
• Numerical modeling with numerical continuation for large amplitudes (non-contact and intermittent modes).
• Experimental validation using a self-developed AFM setup for amplitude-distance curves.

Main Results:

• An analytical model elucidates the influence of damping ratio, excitation frequency, and sample parameters on AFM system behavior.
• The model identifies optimal parameters for maximizing sensitivity.
• Numerical and experimental results validate the analytical model and demonstrate differences between non-contact and intermittent modes.

Conclusions:

• The study provides a unified framework for understanding AFM sensitivity, resolution, and responsivity.
• The derived models enable the optimization of AFM parameters for improved measurement sensitivity.
• The developed experimental setup offers a flexible platform for AFM amplitude-distance curve measurements.