Impact of Electrostatic Forces in Contact Mode Scanning Force Microscopy

TL;DR

This study investigates how surface charges influence contact-mode scanning force microscopy, revealing that electrostatic interactions are detectable mainly with soft cantilevers and are explained by a model involving tip-sample potential alterations.

Contribution

The paper demonstrates the conditions under which electrostatic forces affect measurements, highlighting the role of cantilever stiffness and providing a model for the observed interactions.

Findings

Electrostatic interactions are detectable mainly with soft cantilevers.

Surface charge effects are independent of surface hardness.

A model explains electrostatic influence via tip-sample potential modification.

Abstract

In this $\ll$ contribution we address the question to what extent surface charges affect contact-mode scanning force microscopy measurements. % We therefore designed samples where we could generate localized electric field distributions near the surface as and when required. % We performed a series of experiments where we varied the load of the tip, the stiffness of the cantilever and the hardness of the sample surface. % It turned out that only for soft cantilevers could an electrostatic interaction between tip and surface charges be detected, irrespective of the surface properties, i.\,e. basically regardless its hardness. % We explain these results through a model based on the alteration of the tip-sample potential by the additional electric field between charged tip and surface charges.