Russell Ohl

Russell Shoemaker Ohl (January 30, 1898 – March 20, 1987) was an American scientist who is generally recognized for patenting the modern solar cell (, "Light sensitive device").

Ohl was a notable semiconductor researcher prior to the invention of the transistor. At the time hardly anyone knew anything about the impurities within these crystals, but Russell Ohl discovered the mechanism by which it worked. It was the impurities which made some sections more resistant to electrical flow than others, and thus it was the "barrier" between these areas of different purity that made the crystal work. Ohl later found that super-purifying germanium was the key to making repeatable and usable semiconductor material for diodes. All diodes (incl. LEDs, laser diodes etc.) are descendants of Ohl's work. His work with diodes led him later to develop the first silicon solar cells.