Walter Hans Schottky (23 July 1886 – 4 March 1976) 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, co-invented the ribbon microphone and ribbon loudspeaker along with Dr. Erwin Gerlach in 1924 and later made many significant contributions in the areas of semiconductor devices, technical physics and technology.

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.

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.

In 1924, Schottky co-invented the ribbon microphone along with Erwin Gerlach.

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.

Possibly, in retrospect, Schottky's most important scientific achievement was to develop (in 1914)

In 1923 Schottky suggested (incorrectly) that the experimental phenomenon then called autoelectronic emission and now called field electron emission resulted when the barrier was pulled down to zero.

In fact, the effect is due to wave-mechanical tunneling, as shown by Fowler and Nordheim in 1928.

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.

In 1964 he received the Werner von Siemens Ring honoring his ground-breaking work on the physical understanding of many phenomena that led to many important technical appliances, among them tube amplifiers and semiconductors.

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.

Books written by Schottky Thermodynamik, Julius Springer, Berlin, Germany, 1929.