TUNNEL DIODE: DEFINITION, WORKING, CHARACTERISTICS & APPLICATIONS
The heavily doping of PN junction is called tunnel diode in which the relation between voltage and current is inversely i.e. the voltage increases as the electric current decreases. The tunnel diode is a fast switch and is used in a variety of system and high frequency oscillators and voice amplification circuits.
The operation of the tunnel diode depends on the principle known as tunneling. In electronics, the tunneling is direct flow of electrons in a small depletion region from N side conduction band to the p side of valance band.
WHAT IS A TUNNEL DIODE?
The tunnel diode is also called Eaki diode. The semiconductor diode has “negative resistance” characteristics. Property and this effect are called tunneling. The tunnel diode is a heavily doping of normal PN diode that is about 10 nm wide. Heavy doping is cause of broken band space, where the electron of the conduction band is more or less aligned with the valence band holes.
The tunnel diode is a negative resistance element. The doping concentrations of P and N region in range of 1024–1025 m-3.
For making the tunnel diode commonly use germanium element. This diode can also use another type of element for such as gallium arsenide, gallium antimonite, and silicon.
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