How does current flow in a PN junction?
In a forward-biased PN junction, once the barrier voltage is overcome, it conducts a current. The externally applied potential pushes majority carriers toward the junction where recombination takes place, allowing current flow.
How is the electric field across pn junction created?
PN Junction Distance Then the presence of impurity ions on both sides of the junction cause an electric field to be established across this region with the N-side at a positive voltage relative to the P-side. The result of this process is that the PN junction has rectifying current–voltage (IV or I–V) characteristics.
What do you mean by PN junction?
A p–n junction is a boundary or interface between two types of semiconductor materials, p-type and n-type, inside a single crystal of semiconductor. This allows electrical current to pass through the junction only in one direction.
How does current flow in a depletion region?
When bias is strong enough that the depletion region becomes very thin, the diffusion component of the current (through the junction interface) greatly increases and the drift component decreases. In this case, the net current flows from the P-side to the N-side.
What is the direction of electric field in PN junction?
The direction of electric field is from N- side to P-side in PN junction diode.
Why is it called depletion region?
The depletion region is so named because it is formed from a conducting region by removal of all free charge carriers, leaving none to carry a current.
Why is PN junction used?
p-n junction diode can be used as a photodiode as the diode is sensitive to the light when the configuration of the diode is reverse-biased. It can be used as a solar cell….Applications of PN Junction Diode.
|Semiconductor Diode||Zener Diode|
|Extrinsic Semiconductors||Electric Field Lines|
What is the main function of pn junction?
A p-n junction represents an electrical component with the function to allow an electric current in one direction (called the forward biased condition) and to block the current in the opposite direction (the reverse biased condition): a diode.
What causes the depletion region?
The depletion region is caused by the diffusion of charges. The holes and the electrons diffusing towards each other combine near the junction. In doing so positive and negative ions are formed. The pair of positive and negative ions at the junction forms the dipole.
How is a p-n junction connected to a circuit?
A direct current flows from the positive terminal through the circuit to the negative terminal. There are therefore two ways that we can connect a p-n junction to the circuit. We can connect the p-side to the positive terminal and n-side to the negative terminal, which is called forward bias.
Why does voltage increase in the reverse direction of a PN junction?
In the reverse bias the voltage increases in the reverse direction across the p-n junction, but no current due to the majority carriers, only a very small leakage current flows. But at a certain reverse voltage p-n junction breaks in conduction. It is only due to the minority carriers.
How does junction capacitance work in a capacitor?
Junction Capacitance. When a voltage or potential difference is applied across a capacitor the charges accumulates at the electrodes. The voltage will not move through the dielectric. But the dielectric medium will allow an electric field to flow through it when huge number of charges accumulates at the electrodes.
When is a PN junction diode reverse biased?
A PN junction is said to be reversed biased when the positive terminal of the battery is connected to the n-region and the negative terminal of the battery is connected to the p-region of the PN junction diode. Hence the junction resistance increases.