Electron Microscope Invention: A Historical Overview

History of Electron Microscope (1930-1980)

Nowadays, the electron microscope is an essential instrument to characterize new structures and materials and electron microscope invention has become a popular topic for scientific research. In a typical electron microscope a beam of electrons is focused upon a target specimen. Information is often gathered from electrons transmitted through or scattered from the specimen by Bragg diffraction, alongside data gathered from Auger electrons, characteristic x-rays, and the charge absorbed by the specimen. On the basis of particle-wave duality theory of de Broglie, electrons can replace photons in a microscope to improve the image resolution more than 5000 times.

First Electron Microscope Inventors

The first prototype of electron microscope, that imaged transmitted electrons from the sample with 400 power magnification, was presented in Technical University of Berlin by Ernst Ruska and Max Knoll in 1931, which brought 1986 Noble Prize in physics for Ruska for his “fundamental work in electron optics and for the design of the first electron microscope” (Figure 1).

Later in 1938, the first commercial transmission electron microscope (TEM) was made by Ruska and Bodo von Borries in Siemens.

Scanning Electron Microscope Invention

First scanning-tunneling electron microscope was invented by Manfred Von Ardenne in 1937 (Figure 2). Ruska developed a scanning electron microscope in the 1940s. It utilized electromagnetic lenses to focus scanning electron beam on the target surface and then collected scattered electrons, containing information on the sample topography and structure. You can read more details of SEM here …

Commercial SEMs

Afterward, electron microscopes improved rapidly in the 1950s, when developing scanning electron microscope in Charles Oatley’s laboratory at Cambridge University led to the first commercial scanning electron microscope by Cambridge Instruments in 1965.

One type of SEMs that provides high image quality is FESEM (Field Emission Scanning Electron Microscope). If you are interested in FESEM, you can read more about it below.

Electron Microscope Developments

Since 1970s, determination of crystal structure made easier by tilting the specimen stage. In 1980s and 1990s the environmental electron microscopes allowed researchers to inspect samples under more natural conditions of temperature and pressure.

Vac Coat Ltd. Products

The samples investigated by electron microscopy should be conductive, to prevent charging effect on the sample surface. Consequently, non-conductive samples are coated by a thin conductive film. Vac Coat rotary-backed pump sputter coating systems DSR1 and DSCR are capable of coating thin films of conductive metals and carbon for SEM sample preparation.

High vacuum magnetron sputter coater (DST1) and desk sputter and carbon coater (DSCT), equipped with turbomolecular pump, are promising deposition systems for SEM/FESEM sample preparation and deposition of different targets, providing optional thermal evaporation and plasma cleaning, used to make hydrophilic surfaces and clean TEM grids.

References

1. https://excite-network.eu/about/history/a-short-history-of-electron-microscopy-in-earth-materials-science/
2. https://www.thermofisher.com/blog/materials/the-history-of-the-electron-microscope/
3. https://en.wikipedia.org/wiki/Electron_microscope#History
4. https://www.thermofisher.com/blog/materials/the-history-of-the-electron-microscope/
5. https://www.keyence.com/ss/products/microscope/bzcasestudy/study/history_development.jsp
6. https://www.vonardenne.biz/en/company/mva/
7. https://authors.library.caltech.edu/5456/1/hrst.mit.edu/hrs/materials/public/ElectronMicroscope/
8. http://www-g.eng.cam.ac.uk/125/achievements/mcmullan/mcm.htm