Walter Schottky (; 23 July 1886 – 4 March 1976) was a German physicist and electrical engineer who played a major early role in developing the theory of thermionic emission, invented the screen-grid vacuum tube in 1915, co-invented the ribbon microphone and ribbon loudspeaker along with Erwin Gerlach in 1924, and later made many significant contributions in the areas of semiconductor devices, technical physics, and technology.

The Schottky effect (a thermionic emission; important for vacuum tube technology), the Schottky diode (where the depletion layer occurring in it is called the Schottky barrier), the Schottky vacancies (or Schottky defects), the Schottky anomaly (a peak value of the heat capacity), and the Mott–Schottky equation (also Langmuir–Schottky space charge law) are named after him. He conducted research on electrical noise mechanisms (shot noise), space charge, especially in electron tubes, and the barrier layer in semiconductors, which were important for the development of copper oxide rectifiers and transistors.

Biography

Walter Schottky was born on 23 July 1886 in Zurich, Switzerland, the son of mathematician Friedrich Schottky, who had been appointed a professor at the University of Zurich in 1882. The family moved back to Germany in 1892, where his father took up an appointment at the University of Marburg.

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In 1904, Schottky graduated from in Berlin. He studied under Max Planck and Heinrich Rubens at the University of Berlin, where he received his Ph.D. in 1912 with a thesis titled Zur relativtheoretischen Energetik und Dynamik (On Relativistic Energetics and Dynamics).

In 1912, Schottky began his postdoctoral studies at the University of Jena. In 1914, he joined the low-current laboratory of Siemens & Halske in Berlin. He then lectured at the University of Wuerzburg from 1919 to 1922, receiving his habilitation in 1920. He was Professor of Theoretical Physics at the University of Rostock from 1923 to 1927, when he returned to Siemens & Halske. In 1943, due to the Second World War, Schottky moved from Berlin to Pretzfeld, where he worked in a semiconductor laboratory of Siemens-Schuckert. He also worked in Erlangen from 1955 to 1958.

Inventions

The invention of superheterodyne is usually attributed to Edwin Armstrong. However, Schottky published an article in the Proceedings of the IEEE that may indicate he had invented and patented something similar in Germany in 1918.

The Frenchman Lucien Lévy had filed a claim earlier than either Armstrong or Schottky, and eventually his patent was recognized in the US and Germany.

In 1924, Schottky co-invented the ribbon microphone along with Erwin Gerlach. The idea was that a very fine ribbon suspended in a magnetic field could generate electric signals. This led to the invention of the ribbon loudspeaker by using it in the reverse order, but it was not practical until high flux permanent magnets became available in the late 1930s.

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Commemorations

The Walter Schottky Institute for semiconductor research and the Walter Schottky Prize for outstanding achievements in solid-state physics are named after him.

The Walter Schottky House of the RWTH Aachen University and the Walter Schottky Building of the of Applied Sciences in Nuremberg are also named after him. The Fraunhofer Institute for Integrated Systems and Device Technology is located on in Erlangen.

Books

  • Thermodynamik, Julius Springer, Berlin, Germany, 1929.
  • Physik der Glühelektroden, Akademische Verlagsgesellschaft, Leipzig, 1928.

See also

  • Schottky transistor
  • Schottky junction solar cell
  • Surface-barrier transistor

References

  • Walter Schottky
  • Biography of Walter H. Schottky
  • Walter Schottky Institut
  • Reinhard W. Serchinger: Walter Schottky&nbsp;– Atomtheoretiker und Elektrotechniker. Sein Leben und Werk bis ins Jahr 1941. Diepholz; Stuttgart; Berlin: GNT-Verlag, 2008.
  • Schottky's math genealogy