who developed the first si semiconductor device?
Greenleaf Whittier Pickard
Silicon
 The first silicon semiconductor device was a silicon radio crystal detector, developed by American engineer Greenleaf Whittier Pickard in 1906. 
where is silicon most commonly found on earth More than 90% of the Earth's crust is composed of silicate minerals when was it discovered? Due to the abundance of silicon in the Earth's crust, natural silicon-based materials had been used for thousands of years
wiki:19613907
Silicon [SEP] 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.