Field-emission microscopy

Article By:

Tsong, Tien-Tzou Department of Physics, Pennsylvania State University, University Park, Pennsylvania.

Last reviewed:June 2020

DOI:https://doi.org/10.1036/1097-8542.256210

A technique that uses field emission of electrons or positive ions from a needle-shaped emitter to produce a magnified image of the emitter surface on a fluorescent screen. In the field electron microscope, the image reveals the variation in work function of the emitter surface. Because of the large lateral velocity of the emitted electrons, a resolution of only about 2.5 nanometers (nm) can be achieved. The large lateral velocity arises from a diffraction effect of the de Broglie wave and the large kinetic energy of electrons inside the metal; these effects are intrinsic quantum properties of particles and cannot be eliminated. The field electron microscope has been used to study adsorption and desorption of gases and vapor-deposited materials, surface migration of adsorption layers and absorbed atoms on single crystal faces, and surface reactions in catalysis. Medium-sized individual molecules such as phthalocyanin have been made visible also. See also: De Broglie wavelength; Electron microscope; Field emission; Work function (electronics)

The content above is only an excerpt.