Lilienfeld's early career, at the University of Leipzig, saw him conduct important early work on electrical discharges in "
vacuum", between metal electrodes, from about 1910 onwards. His early passion was to clarify how this phenomenon changed as vacuum preparation techniques improved. More than any other scientist, he was responsible for the identification of
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 was explained by
Fowler and
Nordheim in 1928. Lilienfeld moved to the United States in 1921 to pursue his patent claims, resigning his professorship at Leipzig to stay permanently in 1926. In 1928, he began working at Amrad in
Malden, Massachusetts, later called Ergon Research Laboratories owned by
Magnavox, which closed in 1935. for a FET-like transistor was granted January 28, 1930.) When
Brattain,
Bardeen, and their colleague chemist
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 strike 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==