Influence of pixelization on height measurement in atomic force microscopy

Area of Science:

• Nanoscience
• Surface Science
• Materials Science

Background:

• Atomic Force Microscopy (AFM) offers high resolution for surface topography.
• Accurate height measurements of protruding features can be challenging due to AFM's raster scanning.
• Pixelization effects in AFM imaging are not fully understood, especially for particle height determination.

Purpose of the Study:

• To quantify the impact of pixelization on apparent height measurements of spherical and cylindrical particles using AFM.
• To investigate how AFM probe size influences these pixelization effects.
• To provide insights for accurate interpretation of AFM data and nanoparticle height estimation.

Main Methods:

• Utilized Monte Carlo simulations to model AFM scanning of particles.
• Varied pixel size and AFM probe dimensions in the simulations.
• Analyzed the mean apparent height (hmean) of simulated particles.

Main Results:

• Apparent height (hmean) can be an increasing or decreasing function of pixel size, depending on particle size distribution.
• AFM pixelization can lead to both under- and overestimation of true particle diameters.
• Including AFM probe size significantly increases the underestimation of particle height, up to 50%.

Conclusions:

• Pixelization in AFM introduces significant errors in height measurements, influenced by particle size and probe dimensions.
• Understanding these effects is crucial for accurate AFM data interpretation in nanoscience.
• The findings aid in estimating true nanoparticle heights from AFM images, even at low resolutions.