Atomic Force Microscopy (AFM)

Atomic force microscopy probes a surface not with light or electrons, but mechanically: using a fine tip mounted on a flexible cantilever.

How it works

As the tip is scanned line by line across the sample, forces between the tip and the surface cause tiny deflections of the cantilever. These deflections are measured optically and used to reconstruct a high-resolution height profile of the surface.

Measurement modes

• Contact mode: the tip stays in constant contact with the sample.
• Non-contact mode: the tip oscillates just above the surface without touching it.
• Tapping mode: a hybrid approach where the tip briefly and periodically touches the surface — gentler on delicate samples.

Strengths

AFM achieves lateral resolution in the nanometer range and can measure a variety of forces — including van der Waals, electrostatic, and mechanical interactions. That versatility spans applications from semiconductor analysis to studying individual biomolecules.