Improved acoustic excitation of atomic force microscope cantilevers in liquids

Abstract

A simple modification of the existing setup used in the commercial atomic force microscopes (AFM) is presented with the aim of improving the piezoacoustic excitation in liquid used by the AFM community. The improvement removes the spurious peaks not corresponding to the resonance frequencies of the cantilever oscillation. To illustrate the benefits of such a clean excitation, very fine effects like the structuring of mesitylene confined between the oscillating AFM tip and a highly oriented pyrolitic graphite surface could be measured with subangstrom oscillation amplitudes and with very high accuracy.