Squeezing out hidden force information from scanning force microscopes

Abstract

A method to measure force-separation curves with a scanning force microscope is presented. Forces within the “snap to contact” are obtained by high-speed (MHz) measurement of cantilever deflection signals analyzed using the generalized beam theory. Numerical simulation is used to demonstrate the effectiveness of the method. Experimental results show that the method yields complete continuous force-separation curves with flimsy cantilevers in fluids allowing for sensitive force measurements in nonvacuum environments.