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PN junction diode is a small step and one of the most rigid structures that technology about semiconductors offers in electronics. Bipolar junctions, MOSFETs, and junction FETs or LEDs are otherwise known as light-emitting diodes, and ICs, better known as integrated circuits, are all backed up by semiconductor technology.
The best semiconductor PN junction diode property is for integrating electrons in the flow in one direction and across. This results in it acting as an Alternating Current rectifier. The basis of understanding all semiconductor diodes is an essential operation. This diode is observed as a specific bipolar semiconductor device. The voltage and current curve can differentiate an ideal diode.
Working of PN Junction Diode
If an external voltage is applied to the PN junction diode terminable, potential alteration between the P and N-region will occur. The potential difference can alter majority carriers’ flow for the diffusion of electrons and holes by the PN junction.
If the applied voltage helps decrease the depletion layer width, then the assumed diode will be in forwarding bias, and if vice versa, reverse bias is assumed. If the width of the depletion layer has not altered one bit, then it is in the zero-bias state.
Forward Bias: Potential barrier decreased by the external voltage
Reverse Bias: Built-in potential barrier increased by the external voltage.
Zero Bias: No voltage from exterior applied
Zero Biased
In zero bias, higher potential energy is provided by state junction potential to the holes on both P and N sides. If the PN junction node terminals are shorted few holes in the P side with energy will engulf the potential barrier across the depletion region.
With these holes, the current flow starts initiating in the diode. The holes in the N side will move in a reverse direction toward the depletion zone. Potential barriers oppose and stop electron migration across the PN junction diode and allow charges to drift.
Forward Biased
The voltage is applied externally; a potential difference alteration occurs between P and N regions. When the positive side is connected with P, and the negative side is connected with N, the junction diode is connected in forwarding bias. It brings potential across the junction.
A good amount of carriers of charge in P and N regions are attracted in the direction of the PN junction. Thus the width of the depletion layer decrease and diffusion of several charges occur. The biasing that is external causes derailment from a state of equilibrium.
This way, the electric field is induced inversely to that of a field. The amount of charge Q stored is proportional to Current I in diode flowing. The current that is flowing up to build in potential is Zero Current.
Reverse Biased
When the positive side connects to the N side and P connects to the negative, the junction diodes are connected as reverse bias. In this connection, most charge carriers are decreased away from the depletion layer by the terminals connected to the PN junction. The positive terminal attracts electrons away while the junction on the N side will attract holes away from P side. This will lead to a potential barrier increase and hence impedance of flow of majority carriers.
The free space charge layer width increase, so the PN junction diode electric field increases, and thus PN junction diode acts as a resistor. No current flows through the PN junction diode when the amount of external voltage is increased. A reverse breakdown has a dependence on P and N regions doping levels.
Conclusion
Semiconductors contain the properties in the middle of conductors and insulators. Electrons and holes are charge carriers in semiconductors. Holes are said to be positively charged, while electrons as negatively charged. For electric current conduction, charge carriers are primarily responsible. They are N-type and P-type are two types of extrinsic semiconductors.
PN junction diode formation is by N-type and P-type semiconductors. The P and N junction is free of carrier charge; hence the region is the depletion region. The width of the game is altered by the external voltage applied. If the voltage that is applied help in decreasing the depletion layer width, then the assumed diode will be in forwarding bias and if vice versa, reverse bias is assumed. If the width of the depletion layer has not altered one bit, then it is in the zero-bias state.
