Experimental Methods for the Calibration of Lateral Forces in Atomic Force Microscopy

Abstract

As a variation of atomic/scanning force microscopy (AFM/SFM), lateral force microscopy (LFM) relies on the torsional deformation of the AFM cantilever upon lateral forces acting between tip and sample surface. LFM enables imaging of frictional properties of the surfaces of materials, thin films or monolayers at a high spatial resolution. Furthermore, LFM is increasingly used to study the effect of shear loading on nanostructures or nanoparticulates. Albeit a large variety of applications have been demonstrated and the measurement mode is implemented in most commercially available AFM instruments, LFM seems to suffer from the lack of reliable and established calibration methods for lateral forces. However, general acceptance of LFM requires quantification coupled with a solid understanding of the sources of uncertainty. This chapter reviews the available experimental calibration methods. In addition to a description of these methods, a table including information on the key characteristics is provided as well as an overview of the basic equations.