Walter H. Schottky

Walter 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.