Atomic force microscopy lateral force calibration using a V-shape scratch made by a nanoindenter

Measuring quantitative and accurate friction force at the nanoscale by means of atomic force microscopy is not straightforward. Numerous lateral force calibration methods have been proposed in the last decades. The most popular one is the wedge method that requires a specific calibration sample having areas that present constant slope and friction coefficient. In this paper, we propose to revisit the wedge method by using an original, cheap, and easy-to-make standard, which consists of a V-shaped scratch made by a Berkovich nanoindenter tip on a fused silica substrate. We show that the scratch has two large opposite facets characterized by the same moderate and constant friction coefficient and slope. This allows simplification of the data processing and a much more reliable and accurate lateral force microscopy calibration.