Tunnel diode

Symbol of the Diodo Tunnel

The Tunnel diode is a semiconductor diode that has a pn junction, in which the tunneling effect is produced, giving rise to a negative differential conductance in a certain interval of the current-voltage characteristic.

The presence of the section of negative resistance allows its use as an active component (amplifier/oscillator).

They are also known as Esaki diodes, in honor of the Japanese physicist Leo Esaki who discovered that heavy contamination with impurities could cause a tunneling effect of charge carriers along the zone of depletion at the junction. An important characteristic of the tunnel diode is its negative resistance over a given range of forward-bias voltages. When the resistance is negative, the current decreases with increasing voltage. Consequently, the tunnel diode can function as an amplifier, as an oscillator, or as a flip-flop. Essentially, this diode is a low power device for applications involving microwaves that are relatively free from the effects of radiation.

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