High-speed atomic force microscopy in slow motion--understanding cantilever behaviour at high scan velocities

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Contact mode atomic force microscopy (AFM) is crucial for nanoscale imaging.
• Image artifacts in high-speed AFM can limit resolution and data accuracy.
• Understanding cantilever dynamics is key to improving AFM performance.

Purpose of the Study:

• Identify noise sources in contact mode high-speed AFM images.
• Determine the cantilever dynamics responsible for image artifacts.
• Develop and demonstrate a method to remove these artifacts for enhanced imaging.

Main Methods:

• Utilized scanning laser Doppler vibrometry (SLDV) to analyze cantilever dynamics.
• Reconstructed animations of the cantilever's motion over various surfaces.
• Compared tip displacement monitoring versus tip deflection monitoring during imaging.

Main Results:

• Identified higher eigenmode oscillations along the cantilever as the cause of image artifacts.
• Demonstrated that monitoring tip displacement eliminates these artifacts.
• Showcased the significant advantage of displacement detection for high-speed AFM imaging of a calibration grid.

Conclusions:

• Higher eigenmode oscillations in the cantilever are a primary source of noise in high-speed AFM.
• Switching from deflection to displacement detection is a viable strategy to mitigate these artifacts.
• Displacement monitoring offers superior performance for high-speed AFM imaging applications.