Cantilever dynamics and quality factor control in AC mode AFM height measurements.

We show that inconsistent-imaging dynamics, in which the cantilever oscillates in the attractive regime on substrate background but in the repulsive regime on sample, leads to artifacts in apparent height in AC mode Atomic force microscopy. Active Q control can be used to effectively tune the imaging dynamics. Increased effective Q promotes the attractive regime, improves imaging sensitivity, and results in less invasive imaging of soft biological molecules.