section_path: History/Silicon semiconductors
section_name: Silicon semiconductors
paragraph_text: Silicon semiconductors
  
  The first semiconductor devices did not use silicon, but used galena, including German physicist Ferdinand Braun 's crystal detector in 1874 and Indian physicist Jagadish Chandra Bose 's radio crystal detector in 1901. The first silicon semiconductor device was a silicon radio crystal detector, developed by American engineer Greenleaf Whittier Pickard in 1906.
  
  In 1940, Russell Ohl discovered the p–n junction and photovoltaic effects in silicon. In 1941, techniques for producing high-purity germanium and silicon crystals were developed for radar microwave detector crystals during World War II. In 1947, physicist William Shockley theorized a field-effect amplifier made from germanium and silicon, but he failed to build a working device, before eventually working with germanium instead. The first working transistor was a point-contact transistor built by John Bardeen and Walter Brattain later that year while working under Shockley. In 1954, physical chemist Morris Tanenbaum fabricated the first silicon junction transistor at Bell Labs. In 1955, Carl Frosch and Lincoln Derick at Bell Labs accidentally discovered that silicon dioxide (SiO) could be grown on silicon, and they later proposed this could mask silicon surfaces during diffusion processes in 1958.