Electrostatic force microscopy (EFM) is a type of dynamic non-contact atomic force microscopy where the electrostatic force is probed. ("Dynamic" here means that the cantilever is oscillating and does not make contact with the sample). This force arises due to the attraction or repulsion of separated charges. It is a long-ranged force and can be detected 100nm from the sample. For example, consider a conductive cantilever tip and sample which are separated a distance z usually by a vacuum. A bias voltage between tip and sample is applied by an external battery forming a capacitor, C, between the two. The capacitance of the system depends on the geometry of the tip and sample.

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Mapping local differences in the surface potential. Based on the AFM, but using a conductive tip when a voltage is applied. The available information depends on the capacitance probe/sample and the surface potential.

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