Field emission microscopy (FEM) is an analytical technique used in materials science. Invented by Erwin Müller in 1936, the FEM was one of the first surface analysis instruments that approached near-atomic resolution. The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... Erwin Wilhelm Müller (June 13, 1911 – May 17, 1977) was a German-born physicist who invented the field emission microscope, the field ion microscope, and the atom probe. ...
FEM consists of a sharp needle emitter and a detector, such as a fluorecent screen. A negative electric field is applied to the emitter, emitting electrons from the surface. An image is formed at the detector due to the different current densities, which originates from the difference in electric fields and work functions on the emitter surface by the Fowler-Nordheim equation. The Fowler-Nordheim equation relates current, work and electronic field strength and has two parts: an equation for field emitted current density, and the equation for total current. ...
The field ion microscope is a type of microscope that can be used to image the arrangement of atoms at the surface of a sharp metal tip.
Gas atoms adsorbed on the tip are ionized by the strong electric field in the vicinity of the tip (thus, "field ionization"), becoming positively charged and being repelled from the tip.
Although this is true for many types of microscopes, it is not true for the FIM or other microscopes in which magnification is due to point projection.
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