Robert Noel Hall (December 25, 1919 – November 7, 2016) was an American engineer and applied physicist. He demonstrated the first semiconductor laser and invented a type of

magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave oven, microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of ...

commonly used in

microwave ovens A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...

. He also contributed to the development of rectifiers for power transmission.

Early life

Robert N. Hall was born on December 25, 1919, in

New Haven, Connecticut New Haven is a city of the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound. With a population of 135,081 as determined by the 2020 United States census, 2020 U.S. census, New Haven is List ...

. He was first inspired by his inventor uncle, who showed him the wonders of small inventions and experimentation. After long studies at his local library, Hall decided to attempt controlled experiments of his own with his mother's approval. He built an 8-inch telescope, which produced a close-up view of Saturn. Later on, an interviewer from the

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

visited him and offered a scholarship to attend the university. Hall studied there for three years but had to leave for financial reasons. After working at Lockheed Aircraft as a tester, he returned to Caltech to finish up his studies and obtain his physics degree.

Career

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

hired Hall as a test engineer at

Schenectady, New York Schenectady ( ) is a City (New York), city in Schenectady County, New York, United States, of which it is the county seat. As of the United States Census 2020, 2020 census, the city's population of 67,047 made it the state's ninth-most populo ...

. After four years at

, under the advice of Harper North, Hall obtained a Research Council Fellowship and returned to Caltech. He graduated in 1948 with his Ph.D. and returned to

. Schenectady research labs that summer. While at

during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, he developed a

for radar jamming, which led to the development of the

microwave oven A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...

. While studying the characteristics of p-i-n diodes used as power rectifiers, Hall had a key insight, which resulted in his being co-credited with

William Shockley William Bradford Shockley ( ; February 13, 1910 – August 12, 1989) was an American solid-state physicist, electrical engineer, and inventor. He was the manager of a research group at Bell Labs that included John Bardeen and Walter Houser Brat ...

and W. T. Read, Jr., for the analysis of nonradiative carrier recombination in

semiconductors A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping levels ...

. Hall developed the first semiconductor

laser diode file:Laser diode chip.jpg, The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emittin ...

in 1962, while working at

. In the 1970s, Hall's work focused on

photovoltaics Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commerciall ...

and

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

s. He retired in 1987, having been granted 43 U.S.

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

s during his career. Hall was elected to the

National Academy of Engineering The National Academy of Engineering (NAE) is an American Nonprofit organization, nonprofit, NGO, non-governmental organization. It is part of the National Academies of Sciences, Engineering, and Medicine (NASEM), along with the National Academ ...

in 1977 and to the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

in 1978. He was inducted into the

National Inventors Hall of Fame The National Inventors Hall of Fame (NIHF) is an American not-for-profit organization, founded in 1973, which recognizes individual engineers and inventors who hold a US patent of significant technology. Besides the Hall of Fame, it also operate ...

in 1994.

Personal life

Robert was a Methodist. He died on November 7, 2016, at the age of 96. Death notice published by Hall's family.

Early life

Career

Personal life

References

Further reading