http://nathan.instras.com/documentDB/paper-44.pdf

Surface photovoltage phenomena: theory, experiment, and applications

An experimental investigation of the static electrification of metal/metal surfaces shows that the erratic results normally obtained are owing to there being more than one cause, and that the complete elimination of rubbing leaves an effect that is amenable to quantitative measurement. This ‘separation charging’ is shown to be related to the contact potential, and to have the characteristics to be expected if the Volta-Helmholz hypothesis of its origin is correct. The importance of this explanation of tribo-electrification has long been debated. The supposition that the hypothesis predicts negligible charging of conductor/conductor surfaces is shown to be based on an inadequate understanding of the significance of surface topography at the points of contact. By paying proper attention to this, and revising the hypothesis to allow for the transfer of electrons by tunnel effect, a precise theory of separation charging is derived. When applied to the experiments, agreement within the limits of experimental error is obtained, without the introduction of disposable constants.

The Volta effect as a cause of static electrification

An experimental technique has been developed for the absolute measurement of the density of a surface charge on a dielectric. The apparatus is described and includes provision for producing the surface charges by electron and ultra-violet irradiation, and by the contact of metal electrodes of known differences in work function. An account of the absolute calibration procedure is given. An outline of the examination of the fundamental carrier injection and transport mechanism in insulators by surface charge measurement is given.

https://iopscience.iop.org/article/10.1088/0950-7671/44/7/308/pdf

The examination of the electrical properties of insulators by surface charge measurement

We have developed a novel multitip scanning Kelvin probe which can measure changes in biological surface potential ?Vs to within 2 mV and, quasisimultaneously monitor displacement to 48 h) “active” tracking of the displacement and biopotentials developed along and around a plant shoot in response to an environmental stimulus, e.g., differential illumination (phototropism) or changes in orientation (gravitropism). © 1999 American Institute of Physics.

Multitip scanning bio-Kelvin probe

Die Änderung der Austrittsarbeit von Metallen durch eine Gasadsorption

A simple, rugged, and reliable apparatus for the measurement of contact potential differences (in the future abbreviated CPD) by a modified Kelvin method is described. The null circuit using a 6F5 as electrometer tube has a sensitivity of 0.5‐cm scope deflection/mv of CPD/cm2 sample area, which permits the CPD to be determined to 1/100 volt for samples with surface areas as small as two square millimeters. The apparatus was developed for the study of surface characteristics of metals.

W. E. Meyerhof

Papers

A Modified Kelvin Method for Measuring Contact Potential Differences