Russell S. Ohl

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Russell Shoemaker Ohl (born January 1898 near Allentown (Pennsylvania) , † March 1987 ) was an American electrochemist at Bell Laboratories . He is considered to be the discoverer of the pn junction and its sensitivity to light, which was later the basis for solar cells (1954, Bell Labs).

He began his studies at Pennsylvania State University at the age of 16 . In his second year of study he saw a radio for the first time and was the first to hear the SOS call from a ship that was attacked by a German submarine. The following year he took a course in electron tubes . During the First World War he was in the US Army Signal Corps , then went to Westinghouse Electric , studied further at the University of Colorado and switched to AT&T .

He started at ATT's Bell Labs in Holmdel , New Jersey in 1927 . As early as the 1920s, Ohl was concerned with silicon tip diodes for detector receivers and showed in 1926 that, in contrast to those made of copper oxide, they could be used for high frequencies such as radio. This convinced him of the use of silicon in radar research in the 1940s and tried to use silicon and germanium that were as pure as possible and advocated this at Bell Laboratories.

In 1940 he stumbled over the PN barrier (PN junction ) while studying semiconductor crystals . The semiconductor material was deposited and the crucible was cooled. The crystallized ingot was cut into slices and used for experiments. One of his samples had a crack. During resistance measurements on this crystal, he noticed that the resistance changes drastically when exposed to light. With his colleagues, he discovered that the crack had separated the crystal into two zones with different impurities, which they named x and y (later named "P" and "N" types). Immediately after the discovery, the effect was demonstrated at the Bell Lab to his supervisor and research director of the laboratory Mervin Kelly and Walter Brattain , among others .

He patented his silicon solar cell. It was far more effective than selenium photo elements . Commercially, Bell Labs applied this in a photo-tip diode by John N. Shive in 1950 and with the development of pn junctions using diffusion technology in 1954 ( Daryl Chapin , Gerald Pearson , Calvin S. Fuller ).

In 1955 he became a fellow at the Institute of Radio Engineers .

In 1958, when he realized that his lab work was no longer what it used to be, he retired, moved to California with his family and became interested in plants.

Web links

Individual evidence

  1. ^ Riordan, Hoddeson Out of the crystal maze , pp. 462f
  2. ↑ In his oral history interview with Hoddson in 1976, he does not see this as a coincidence, but rather as the result of systematic study of semiconductors, especially with his colleague Jack Scaff
  3. ^ Ohl, Oral History Interview 1976 with Hoddeson
  4. ^ Mark Burgess Diffusion Technologies at Bell Labs , 2010
personal data
SURNAME Ohl, Russell S.
ALTERNATIVE NAMES Ohl, Russell Shoemaker
BRIEF DESCRIPTION American electrochemist
DATE OF BIRTH January 1898
PLACE OF BIRTH near Allentown (Pennsylvania)
DATE OF DEATH March 1987