Julius Edgar Lilienfeld
|J. E. Lilienfeld|
April 18, 1882|
Lemberg, Galicia, Austria-Hungary
|Died||August 28, 1963
Charlotte Amalie, Virgin Islands, USA
|Fields||Physicist and electronic engineer|
|Institutions||University of Leipzig
Ergon Research Laboratories
|Doctoral advisor||Max Planck
|Other academic advisors||Jacobus Henricus van 't Hoff|
Julius Edgar Lilienfeld (April 18, 1882 – August 28, 1963) was an Austro-Hungarian physicist. He was born in Lemberg in Austria-Hungary (now called Lviv in Ukraine), moved to the United States in the early 1920s, and became an American citizen in 1934. Lilienfeld is credited with the first patents on the field effect transistor (1920s) and electrolytic capacitor (1931).
Between 1900 and 1904, Lilienfeld studied at the Friedrich-Wilhelms-Universität (renamed in 1949), in Berlin, where he received his Ph.D. on February 18, 1905. In 1905 he started to work at the physics institute at the University of Leipzig.
Lilienfeld's early career was at the University of Leipzig, where he conducted important early work on electrical discharges in "vacuum", between metal electrodes, from about 1910 onwards. His early passion was to clarify how the phenomena changed as vacuum preparation techniques improved. More than any other scientist, he was responsible for the identification of (presently named) field electron emission as a separate physical effect. (He called it "auto-electronic emission", and was interested in it as a possible electron source for miniaturised X-ray tubes, in medical applications.) Lilienfeld was responsible for the first reliable account in English of the experimental phenomenology of field electron emission, in 1922. The effect itself was explained by Fowler and Nordheim in 1928.
Lilienfeld moved to the United States in the early 1920s, originally in order to defend patents he possessed, and then made a scientific/industrial career there.
Among other things, he invented an "FET-like" transistor and the electrolytic capacitor in the 1920s. He filed several patents describing the construction and operation of transistors as well as many features of modern transistors. (US patent #1,745,175  for an FET-like transistor was granted January 28, 1930.) When Brattain, Bardeen, and Robert Gibney tried to get patents on their earliest devices, most of their claims were rejected due to the Lilienfeld patents.
The optical radiation emitted when electrons are hitting a metal surface is named "Lilienfeld radiation" after he first discovered it close to X-ray tube anodes. Its origin is attributed to the excitation of plasmons in the metal surface.
The American Physical Society has named one of its major prizes after Lilienfeld.
Personal life 
Lilienfeld emigrated to the United States in 1927 and became a US citizen in 1934. He married an American, Beatrice Ginsburg, in New York City on May 2, 1926. They lived in Winchester, Massachusetts, while Lilienfeld was director of the Ergon Research Laboratories in Malden, Massachusetts. In 1935, he and his wife built a house on St. Thomas in the U.S. Virgin Islands in hope of escaping an allergy associated with wheat fields, from which Lilienfeld had suffered for most of his life. Lilienfeld frequently traveled between St. Thomas and various mainland locations and continued to test new ideas and patent the resulting products.
Lilienfeld's patents 
- US 1745175 "Method and apparatus for controlling electric current" first filed in Canada on 22.10.1925, describing a device similar to a MESFET
- US 1900018 "Device for controlling electric current" filed on 28.03.1928, a thin film MOSFET
- US 1877140 "Amplifier for electric currents" filed on 08.12.1928, solid state device where the current flow is controlled by a porous metal layer, a solid state version of the vacuum tube
- US 2013564 "Electrolytic condenser" filed on 29.08.1931, Electrolytic capacitor
See also 
- "A Very Early Conception of a Solid State Device". IEEE Global History Network. IEEE. Retrieved 21 July 2011.
- U.S. Patent 1,745,175 Method and apparatus for controlling electric currents
- Thomas H. Lee, The design of CMOS radio-frequency integrated circuits. Cambridge University Press, 2004 ,p.167ff
- Joel N. Shurkin (8 January 2008). Broken genius: the rise and fall of William Shockley, creator of the electronic age. Palgrave Macmillan. pp. 116–. ISBN 978-0-230-55192-3. Retrieved 10 September 2011.
- J.E. Lilienfeld (1919). "Die sichtbare Strahlung des Brennecks von Röntgenröhren". Physikalische Zeitschrift 20 (12): 280.
- Boersch, Hans; Radeloff, C.; Sauerbrey, G. (1961). "Über die an Metallen durch Elektronen ausgelöste sichtbare und ultraviolette Strahlung". Zeitschrift für Physik A (in German) 165 (4): 464–484. Bibcode:1961ZPhy..165..464B. doi:10.1007/BF01381902.
- Boersch, Hans; Radeloff, C.; Sauerbrey, G. (1961). "Experimental detection of transition radiation". Phys. Rev. Lett. 7 (2): 52–54. Bibcode:1961PhRvL...7...52B. doi:10.1103/PhysRevLett.7.52.
- Christian Kleint, Julius Edgar Lilienfeld: Life and profession. In: Progress in Surface Science, Volume 57, Issue 4, April 1998, Pages 253–327.
- Chih-Tang Sag, Evolution of the MOS Transistor - From Conception to VLSI. In: Proceedings of the IEEE, Vol. 76, No. 10, October 1988, Paage 1280-1326.