Advantages of Tunnel diode | disadvantages of Tunnel diode
This page covers advantages and disadvantages of Tunnel diode. It mentions Tunnel diode advantages or benefits and Tunnel diode disadvantages or drawbacks.
What is Tunnel diode?
The tunnel diodes are heavily doped p-n junction diodes with negative resistance over a portion in its characteristic as shown in the figure-1. They are heavily doped and have very thin depletion zones in order to encourage quantum mechanical tunneling currents to form. It is also called Esaki diode. These diodes are used as amplifiers or oscillators or one-shot multivibrator.
Following are the features of tunnel-diode different compare to normal p-n junction diode.
• Doping levels at p-side and n-side are very high.
• They have very thin depletion zones ( 3 to 100 angstroms).
• Tunneling current consists of majority carriers i.e. electrons from n-side to p-side.
• Preferred semiconductors used in tunnel diode are Ge and GaAs.
Refer Tunnel diode basics and applications >>.
Benefits or advantages of Tunnel diode
Following are the benefits or advantages of Tunnel diode:
➨Current due to majority carriers in tunnel diode responds much faster to voltage changes. This property of tunnel diode is very useful at microwaves for high speed applications.
➨It is a low power device.
➨Large current flows at small value of reverse voltage due to considerable overlap between conduction band and valence band. This is useful property as frequency converter.
➨It exhibits negative resistance characteristic as shown in the figure, which is useful for reflection amplifiers and oscillators.
➨It is a low noise device.
➨It is simple and low cost device.
➨It has low power consumption.
Drawbacks or disadvantages of Tunnel diode
Following are the disadvantages of Tunnel diode:
➨It delivers low output voltage swing. This is less compare to other devices.
➨The power output levels of tunnel diode are restricted to only few milliwatts because the applied DC potential must be less than bandgap potential of the diode.