Walter H. (Hermann) Schottky (July 23, 1886, Zürich, Switzerland March 4, 1976, Pretzfeld, West Germany) was a German physicist who invented the screen-grid vacuum tube in 1915 and the tetrode in 1919 while working at Siemens. In 1938, Schottky formulated a theory predicting the Schottky effect, now used in Schottky diodes.
He was awarded the Royal Society's Hughes medal in 1936 for his discovery of the Schrot effect (spontaneous current variations in high-vacuum discharge tubes, called by him the "Schrot effect": literally, the "small shot effect") in thermionic emission and his invention of the screen-grid tetrode and a superheterodyne method of receiving wireless signals.
Note: The invention of superheterodyne is usually attributed to Edwin Armstrong. However, Schottky published an article in Proc. IRE that he had also invented something similar.
1939: first PN junction
His father was mathematician Friedrich Hermann Schottky (1851–1935).
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