Scanning probe microscopy

From Biology-Online Dictionary | Biology-Online Dictionary

Scanning Probe Microscopy

(Science: technique) Initially called atomic force microscopy, this technique is now more typically termed scanning Force Microscopy or scanning Probe Microscopy.

This instrument is essentially an extremely high resolution profilometre. A sharp tip, typically fabricated from silicon nitride, is scanned across the surface of a sample at a constant force by three piezoelectric ceramics.

The piezoelectric ceramics are computer controlled via a feedback loop which monitors the position of the tip by means of an optical lever. (A laser is focused on the top of the tip support and the beam reflected into a position sensitive detector). The changes in height of the tip are used to form an image as the tip is scanned across the sample.

Acronym: SPM