Walter Hans Schottky was a German physicist who played a major early role in developing the theory of electron and ion emission phenomena, invented the screen-grid vacuum tube in 1915 while working at
Siemens,[2] co-invented the ribbon microphone and ribbon loudspeaker along with Dr. Erwin Gerlach in 1924[3] and later made many significant contributions in the areas of semiconductor devices, technical physics and technology. Schottky’s father was mathematician Friedrich Hermann Schottky .His father was appointed professor of mathematics at the University of Zurich in 1882, and Schottky was born four years later. The family then moved back to Germany in 1892, where his father took up an appointment at the University of Marburg.[citation needed]

Schottky graduated from the Steglitz Gymnasium in Berlin in 1904. He completed his B.S. degree in physics, at the University of Berlin in 1908, and he completed his PhD in physics at the Humboldt University of Berlin in 1912, studying under Max Planck and Heinrich Rubens, with a thesis entitled: Zur relativtheoretischen Energetik und Dynamik (translates as About Relative-Theoretical Energetics and Dynamics).

Schottky’s postdoctoral period was spent at University of Jena (1912–14). He then lectured at the University of Würzburg (1919–23). He became a professor of theoretical physics at the University of Rostock (1923–27). For two considerable periods of time, Schottky worked at the Siemens Research laboratories (1914–19 and 1927–58). In 1914 Schottky discovered an irregularity in the emission of thermions in a vacuum tube, now known as the Schottky effect. He invented the screen-grid tube in 1915, and in 1919 he invented the tetrode, the first multigrid vacuum tube. In his book Thermodynamik (1929), he was one of the first to point out the existence of electron “holes” in the valence-band structure of semiconductors. In 1935 he noticed that a vacancy in a crystal lattice results when an ion from that site is displaced to the crystal’s surface, a type of lattice vacancy now known as the Schottky defect. In 1938 he created a theory that explained the rectifying behaviour of a metal-semiconductor contact as dependent on a barrier layer at the surface of contact between the two materials. The metal semiconductor diodes later built on the basis of this theory are called Schottky barrier diodes.