Tunnel Diode is invented by researcher Leo Esaki in 1957 he received the Nobel Prize in 1973 for discovering the electron tunneling effect used in these diodes. Therefore, it is sometimes known as Esaki Diode, he discovered that by adding high impurities to the normal PN junction diode a diode can exhibit negative resistance in the forward bias. A diode with these high impurities can be used for very fast operation, well into the microwave frequency region, by using quantum mechanical effects. Read More