BACKWARD DIODE

• A diode is a semiconductor part with two ends that is used in almost all electronic products. One can find tunnel, Schottky, zener, LED, PIN, backward, avalanche, laser, varactor, gunn,
• BARITT, and other kinds of diodes on the market. These are used depending on the need. In this case, the backward diode is a type of diode that works in reverse bias mode.
• This diode is like a tunnel diode or a Zener diode, but it works better with small reverse biases than with small forward bias voltages.
• This page gives some basic information about the backward diode, including how it is made, how it works, and what it can be used for.

Backward Diode

• A backward diode, also written "back diode," is a diode that works in reverse-biassed mode. It's a type of PN junction diode that's mostly made to give tunnel diodes and zener diodes different design features.
• This diode works in only one way, so it is called a solitary device. This diode works the same way as Zener and tunnel diodes, even though its working voltages are much lower
• Low-voltage messages between 0.1 volts and 0.6 volts are what the backward diode is for. This diode can also be used as a switch in the multiplier and RF mixer because it can switch quickly.
• Look at this picture of a backward diode that looks like a PN junction diode.
• On the other hand, the anode side (P-type) is the same as the PN junction, while the cathode side (N-type) is slightly different because of the bar.

Backward Diode SymbolBackward Diode Construction

• Aside from the light doping dosage, this diode is built like a tunnel diode.
• One side of the junction is lightly doped, while the other side is heavily doped.
• It helps line up the valance and conduction bands so that it works like a PN junction diode when the bias is applied forward.
• There is no tunnel current or quantum tunnelling when the bias is forward.
• But there is a huge tunnel current when the bias is backward. It is called a backward diode because it has better conduction and smaller resistance when quantum tunnelling only happens in reverse bias.

Working

• The quantum tunnelling concept is all that a backward diode does.
• Quantum tunnelling is a way to use quantum mechanics when wavefunctions can pass through a potential barrier. So the transfer through the potential barrier can be set and changes greatly with the height and width of the barrier.
• This diode works like a tunnel diode, except that the tunnelling happens when the bias is turned around.
• It works like a normal PN junction diode in both forward and reverse bias; in reverse bias, it can carry current better than in forward bias.
• A simple way to explain how this diode works is to look at an energy band diagram for different biases.

Backward Diode V-I Characteristics

• The backward diode's V-I features are shown below. This property demonstrates the main connection between the current and voltage in the device.
• The x-axis shows the voltage across the characteristic, and the y-axis shows the current flowing through it.
• The voltage-current (VI) features of a backward diode are different from those of other diodes.
• If you plot the current going through the diode against the voltage across it, you can see that the VI characteristics of a backward diode behave in a unique way, especially when it is operating in the reverse-biassed mode.

Forward-biassed region

• When the bias is on the forward side, the backward diode works like any other diode.
• The VI characteristics are very close to those of a normal diode, and it lets current run with very little resistance.
• The forward current through the diode grows exponentially as the forward voltage rises. This is the normal behaviour of the diode.

Reverse-biassed region

• In the reverse-biassed area, there is the biggest departure from the normal behaviour of a diode.
• The backward diode doesn't break down in an avalanche like other diodes do; instead, it has an area of negative resistance because of quantum tunnelling effects.
• The VI graph shows that as the reverse voltage goes up, the reverse current goes down in the negative resistance area.
• In normal diodes, the reverse current grows exponentially as the reverse voltage rises during avalanche breakdown. This is the opposite of what happens here.
• In a backward diode, the negative resistance area is the most important part of the VI properties.
• It lets the diode carry current when the bias is reversed, which is useful in some situations, especially when working with high-frequency oscillators, microwave generation, and parametric amplification.

Reverse breakdown region

• If you raise the reverse voltage above a certain point, the backward diode will finally reach a breakdown area where the reverse current rises very quickly.
• The negative resistance region is not the same as this region. This region is similar to how regular diodes behave when they go through avalanche breakdown.
• In the forward-biassed mode, a backward diode's VI characteristics behave like any other diode's. However, in the reverse-biassed mode, they show a unique area of negative resistance because of quantum tunnelling effects.
• Because of this, backward diodes are useful parts in certain situations where negative resistance and special electrical properties are needed.

IMAGE SOURCE (THUMBNAIL)