page_title: Leo Esaki
section_title: Esaki diode
hierarchical_section_title: Leo Esaki / Career / Esaki diode
caption_attribution_description: Japanese physicist Reona Esaki, also known as Leo Esaki works at Sony on June 27, 1959 in Tokyo, Japan
context_page_description: Reona Esaki, also known as Leo Esaki, is a Japanese physicist who shared the Nobel Prize in Physics in 1973 with Ivar Giaever and Brian David Josephson for his work in electron tunneling in semiconductor materials which finally led to his invention of the Esaki diode, which exploited that phenomenon. This research was done when he was with Tokyo Tsushin Kogyo. He has also contributed in being a pioneer of the semiconductor superlattices.
context_section_description: From 1947 to 1960, Esaki joined Kawanishi Corporation (now Fujitsu Ten) and Tokyo Tsushin Kogyo (now Sony). Meanwhile, American physicists John Bardeen, Walter Brattain, and William Shockley invented the transistor, which encouraged Esaki to change fields from vacuum tube to heavily-doped germanium and silicon research in Sony. One year later, he recognized that when the PN junction width of germanium is thinned, the current-voltage characteristic is dominated by the influence of the tunnel effect and, as a result, he discovered that as the voltage is increased, the current decreases inversely, indicating negative resistance. This discovery was the first demonstration of solid tunneling effects in physics, and it was the birth of new electronic devices in electronics called Esaki diode (or tunnel diode). He received a doctorate degree from UTokyo due to this breakthrough invention in 1959.
  In 1973, Esaki was awarded the Nobel Prize for research conducted around 1958 regarding electron tunneling in solids. He became the first Nobel laureate to receive the prize from the hands of the King Carl XVI Gustaf.
caption: Leo Esaki works at Sony on June 27, 1959 in Tokyo, Japan
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