Electrostatic Force Microscopy
EFM is a technique (based on noncontact atomic force microscopy nc‐AFM) to directly measure the electrostatic force between tip and sample. This force arises due to the attraction or repulsion of separated charges. It is a long-range force and can be detected 100 nm or more from the sample. In EFM an applied bias voltage is used to excite the cantilever oscillation, whose amplitude depends on the electrostatic force interaction between the AFM tip and the sample.
EFM can be used to study the local variation of surface charge carriers. It can also be used for studying capacitance, surface potential, dopant distribution or dielectric properties of metallic and insulating surfaces.