December 16: The first point-contact transistor was built (1947)

William Bradford Shockley, John Bardeen and Walter Houser Brattain built a point-contact transistor at Bell Laboratories. A point-contact transistor was the first type of solid-state electronic transistor ever built. Germanium was used for semiconductor material in this experiment and it had been used as major material for semiconductors for two decades until it was replaced by silicon and other materials. The point-contact transistor was quickly superseded by the junction transistor. Transistors were the beginning of the revolution made by integrated circuits.