Gerald Pearson
Gerald Leondus Pearson was an influential American physicist and electrical engineer, born on March 31, 1905, in Salem, Oregon. He earned his bachelor's degree in physics and mathematics from Willamette University and later obtained a master's degree from Stanford University. Pearson's work at Bell Telephone Laboratories during and after World War II was pivotal in the development of semiconductor technology. Alongside notable colleagues like John Bardeen and Walter H. Brattain, he contributed to the invention of the point-contact transistor, which revolutionized electronic circuits.
Although he did not receive a Nobel Prize, Pearson's research laid the groundwork for the junction transistor and photovoltaic cells, technologies that transformed modern electronics and renewable energy. His innovation in creating a field effect in semiconductors and the development of efficient silicon photovoltaic cells significantly advanced the capabilities of electronic devices and solar energy applications. After retiring from Bell Labs in 1960, he continued to influence the field as a professor at Stanford, where he remained active in research until his later years. Pearson passed away on October 25, 1987, leaving behind a legacy that impacted countless technologies used globally today.
Gerald Pearson
American physicist
- Born: March 31, 1905
- Birthplace: Salem, Oregon
- Died: October 25, 1987
- Place of death: United States
Besides playing a supporting role in the invention and improvement of the transistor, Pearson worked with two other principal researchers at Bell Telephone Laboratories to invent the photovoltaic cell, commonly known as the solar cell, which uses sunlight to generate electricity.
Primary fields: Electronics and electrical engineering; physics
Primary invention: Photovoltaic cell
Early Life
Gerald Leondus Pearson was born in Salem, Oregon, on March 31, 1905, to David Shafer Pearson and Sarah Allen Pearson. When he finished high school, he stayed in his hometown to enroll at Willamette University, from which he received a bachelor’s degree in physics and mathematics in 1926. During the next academic year, he taught at a high school and then, in 1927, enrolled at Stanford University, near Palo Alto, California. At Stanford, he majored in physics, carried out experiments with X rays, and earned a master’s degree in 1929. On June 30 of that year, in Rosedale, Oregon, he married Mildred Oneta Cannoy (1906-2000). The newlyweds soon moved to were chosen, where Pearson began work for Bell Telephone Laboratories, initially concentrating on reducing electronic noise and then on developing thermistors, which are resistors that show special sensitivity to temperature. During World War II, he carried out research with a friend and fellow physicist at Bell Labs, Walter H. Brattain, on infrared detectors for U.S. military use.
Life’s Work
By 1945, Pearson, Brattain, and other scientists and engineers were working at the new Bell Labs campus in Murray Hill, New Jersey. Pearson shared an office with Brattain, who smoked cigars with him, and both men joined the research group for semiconductors when the war ended in August. In October, 1945, John Bardeen, another physicist, joined them. Their supervisor was the physicist William Shockley, brilliant but sometimes abrasive.
In its efforts to develop a solid-state amplifier to replace the commonly used vacuum tube, the research group soon concentrated on the semiconductors germanium and silicon, and through experiments Pearson learned how impurities in crystals of those elements affect the flow of electrons and holes (absences of electrons) in the crystals. In addition, he worked with Brattain to try to produce the electric field effect that Shockley had predicted in April, 1945; that is, Pearson and Brattain tried to use an external electric field to control the flow of holes and electrons in very thin layers of semiconductors.
Early in the spring of 1946, Pearson and Brattain had a slight success in creating a field effect in germanium when they used liquid nitrogen to reduce its temperature drastically. In December, 1947, about the time Brattain and Bardeen invented the point-contact transistor (a solid-state amplifier using point contacts), Pearson had a greater success in creating a field effect by using a suggestion from Shockley. On a plate of quartz, Pearson placed a film of positive-type, or P-type, germanium (germanium in which an impurity has produced an excess of holes). With a wire attached to each end of the germanium-coated plate and a little drop of the electrolyte glycol borate on the germanium, he used a wire touching the drop to apply a small voltage, which changed the current in the film significantly. He recorded his success in his laboratory notebook with an entry dated December 12.
On the afternoon of December 23, Pearson spoke briefly at the first presentation to high-level Bell Labs executives of Brattain and Bardeen’s solid-state amplifier. After his talk and the others were over, Pearson and his fellow researchers witnessed the first formal demonstration of this device, this first transistor. Less than three days later, on the snowy morning of December 26, Pearson achieved the field effect without using glycol borate. Using a thin piece of mica with gold on one side and germanium on the other, he applied a voltage to the gold and thus produced a small change in the current in the germanium.
Regrettably, the invention of the point-contact transistor led to a troublesome situation for researchers, such as Pearson, in the semiconductor group. Shockley was too competitive to be entirely happy that Bardeen and Brattain had invented the device without his own close involvement. Furthermore, the discovery that the little-known physicist Julius Lilienfeld had already patented a device depending upon the electric field effect meant that Shockley’s name could not legitimately be on the patent for the point-contact transistor. Pearson avoided taking sides personally in the dispute, but his work pushed him toward Shockley professionally. The issue of Physical Review dated July 15, 1948, contained Shockley and Pearson’s article “Modulation of Conductance of Thin Films of Semi-Conductors by Surface Charges,” which derived from Shockley’s theory and Pearson’s experiments. The two articles by Bardeen and Brattain in the same issue, however, became more important.
With his laboratory skill, Pearson helped Shockley improve the transistor. Building on an experiment performed at Bell Labs by Richard Haynes, Pearson learned how to make very narrow filaments of germanium. Those filaments would let holes or electrons flow with some ease but would nevertheless control the flow. The intent was to lessen electronic noise by doing away with at least one of the metal points of the point-contact transistor. By the middle of August, 1948, Pearson, Shockley, and Haynes had built a filamentary transistor in which only one point contact remained. In a sign that hard feelings lingered between Brattain and Bardeen, on the one hand, and Shockley, on the other, the two direct inventors of the point-contact transistor did not work on the filamentary one. Furthermore, in a reorganization at Murray Hill in the spring of 1951, Brattain and Bardeen joined the physics of solids research group, while Pearson joined the transistor physics research group, led by Shockley.
Pearson therefore played an important part in the development of Shockley’s junction transistor, which Bell Labs announced to the public on July 4, 1951. Depending not at all on point contacts but, in its developed form, on a sandwich-style arrangement with positive-negative junctions, or PN junctions, the junction transistor soon led to the photovoltaic cell, or solar cell, which contains only one PN junction. Actually, Russell Ohl, another Bell Labs colleague, had noticed a strong photovoltaic effect in 1940 when he had shone a flashlight on a silicon rod. Mastery of the manufacture of uniform and pure silicon crystals, however, was necessary for the development of practical photovoltaic cells, as was mastery of doping, the careful contamination of the silicon with certain elements to make it electrically either P-type or N-type.
While researchers at Bell Labs were working successfully at improving techniques for making and doping silicon crystals, Daryl Chapin worked there trying to develop an efficient photovoltaic cell that would use the Sun’s energy to power telephones where no other reliable power was available. In 1952, Pearson was working nearby with Calvin Fuller to build a silicon rectifier to convert alternating current to direct current. To increase conductivity, Fuller doped the silicon with gallium. Then Pearson dipped the gallium-doped silicon into heated lithium. Afterward, he found that, when he exposed the treated silicon to light, it produced an electric current, and he quickly told Chapin. After further work by the three researchers improved the efficiency to Chapin’s goal of 6-percent efficiency, Bell Labs announced the invention to an appreciative public on April 25, 1954.
Pearson remained at Bell Labs until he retired from the company in 1960. In September of that year, he became a professor of electrical engineering at Stanford, where he worked at his own research, especially on compound semiconductors, and helped his students with theirs. Even after his formal retirement from the faculty in 1970, he remained active in research for years. By the time he died, on October 25, 1987, he had earned numerous honors and the respect of physicists and electrical engineers around the world. His wife and two children survived him, as did grandchildren and great-grandchildren.
Impact
Unlike Shockley, Bardeen, and Brattain, Pearson never received a Nobel Prize. Nevertheless, along with them, Chapin and Fuller, and other researchers at Bell Labs, Pearson contributed enormously to electronic technology. In peace or at war, at home or in the office, or on the road between, people in highly developed countries and often in underdeveloped ones depend on instruments containing descendants of the junction transistor that Pearson helped develop. Complex machines such as automobiles, airplanes, and digital computers, all of which existed before the transistor, have come to rely on what Pearson helped bring into the world. As for the photovoltaic cell, it gained use quickly not only for powering telephones in remote places but also for powering satellites orbiting the Earth. By the early twenty-first century, photovoltaic cells produced the electric current for the transistors within the pocket calculator and, on a larger scale, provided the electric current that powered some houses. In the opinion of numerous engineers and scientists, photovoltaic cells promised to yield environmentally harmless energy for everything from the lamps bordering a driveway to the car in it and the building at the driveway’s end.
Bibliography
Ewing, Rex A., and Doug Pratt. Got Sun? Go Solar: Get Free Renewable Energy to Power Your Grid-Tied Home. Masonville, Colo.: PixyJack Press, 2005. An easily readable book that both includes a short account of the development of the solar cell at Bell Labs and presents a guide for homeowners who wish to generate their own electricity with photovoltaic modules or wind turbines. Illustrations, appendixes, bibliography, glossary, index.
Goetzberger, A., and V. U. Hoffmann. Photovoltaic Solar Energy Generation. New York: Springer, 2005. A monograph that presents not only technical information about the generation of electricity through the use of sunlight but also an economic argument to support solar power. Illustrations, bibliography, index.
Ramsey, Dan. The Complete Idiot’s Guide to Solar Power for Your Home. Indianapolis, Ind.: Alpha Books, 2003. Despite the title, a solar enthusiast’s advice and practical information for the intelligent nonspecialist who wishes to build, buy, live in, or sell an energy-efficient, solar-powered house. Illustrations, glossary, appendix, index.
Riordan, Michael, and Lillian Hoddeson. Crystal Fire: The Birth of the Information Age. New York: W. W. Norton, 1997. A lucid, carefully researched account of the invention and early development of the transistor and related devices (including the solar cell), with due attention to Pearson while he worked for Bell Labs. Illustrations, bibliography, index.
Wenham, S. R., M. A. Green, M. E. Watt, and R. Corkish. Applied Photovoltaics. 2d ed. Sterling, Va.: Earthscan, 2007. A textbook for electrical engineers, solid-state physicists, and other appropriately educated persons interested in the details of converting the Sun’s energy into electrical energy. Illustrations, exercises, bibliographies, appendixes, index.