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Profile: Bell Laboratories
- Child organization of AT&T
Bell Laboratories was a participant or observer in the following events:
Semiconductor researcher Russell Shoemaker Ohl of Bell Laboratories is poring over silicon samples, one of which has a crack in the middle. Electrical current flows through the cracked sample when exposed to light. The crack, likely formed when the sample was made, actually marks the boundary between regions containing different levels of impurities, so one side is positively “doped” and the other negatively doped. Ohl has inadvertently created a “p-n junction,” the basis of a solar cell. When an excess positive charge builds up on one side of the p-n barrier, and a similar excess charge builds up on the other, negatively charged side, an electric field is created. The cell can be hooked up into a circuit, and incoming photos striking the cell can “kick” electrons loose and start a current flowing. Ohl patents the solar cell, which operates at about one percent efficiency. [American Physical Society, 2013]
Bell Laboratories scientists Daryl Chapin, Calvin Fuller and Gerald Pearson develop the silicon photovoltaic cell, launching the US’s photovoltaic technology industry. The PV cell is the first to convert enough solar energy to run everyday electrical equipment. Chapin had been working on magnetic materials at Bell Labs, and wanted to develop a source of power for telephone systems in remote humid locations, where dry cell batteries degraded rapidly. Chapin determined that solar energy was the most promising of the alternative energy sources available, but found the existing selenium solar cells (see 1883 and 1940) far too inefficient. Fuller and Pearson were working together to control the properties of semiconductors by introducing impurities. When the two introduce gallium and lithium to a piece of silicon, they create a p-n junction, allowing electrical current to be generated. The silicon cell produces far more electricity than they had anticipated. Pearson informed Chapin to concentrate on silicon cells, and the three work together to improve the properties of the silicon cells. Eventually, the three use a silicon cell with boron and arsenic impurities to create a satisfactory solar cell, and link several together to form what they call a “solar battery.” Their battery produces energy at about a six percent efficiency rating. Bell publicly demonstrates the new battery by using it to power a toy Ferris wheel and a radio transmitter. The New York Times writes that the silicon solar cell “may mark the beginning of a new era, leading eventually to the realization of one of mankind’s most cherished dreams—the harnessing of the almost limitless energy of the sun for the uses of civilization.” Bell Labs later produces a PV cell that achieves 11% efficiency. [US Department of Energy, 2002 ; American Physical Society, 2013]
The US’s Vanguard I space satellite uses a small solar array, generating less than one watt, to power its radios. Later that same year, the Explorer III, Vanguard II, and Sputnik-3 satellites all use PV-powered systems (see 1956-1958) to power its systems. While commercial uses for solar energy in the United States (see 1955) is less than successful during this period, silicon solar cells become a mainstay of satellites and subsequent space exploration vehicles. In 1962, Bell Telephone Laboratories launches the first telecommunications satellite, Telstar. This satellite generates 14 watts of electricity via its PV cells. [US Department of Energy, 2002 ; Smithsonian National Air and Space Museum, 2013]
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