Why we use pn junction diode?

Why we use pn junction diode?

The junction which is the p-n junction diode can be used as a photodiode, the diode which is sensitive to the light when the configuration of the diode is reverse-biased. It can be used as a solar cell. When the diode is forward-biased then it can be used in LED lighting applications.

How does a diode work pn junction?

A diode (PN junction) in an electrical circuit allows current to flow more easily in one direction than another. Forward biasing means putting a voltage across a diode that allows current to flow easily, while reverse biasing means putting a voltage across a diode in the opposite direction.

Why electrons can tunnel through a PN junction?

The main reason why electrons can tunnel through a p-n junction is that. barrier potential is very low. they have high energy. impurity level is low.

How is a pn junction diode formed?

P-n junctions are formed by joining n-type and p-type semiconductor materials, as shown below. However, in a p-n junction, when the electrons and holes move to the other side of the junction, they leave behind exposed charges on dopant atom sites, which are fixed in the crystal lattice and are unable to move.

What are two applications of pn diodes?

Applications of PN Junction Diode

• 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.
• When the diode is forward-biased, it can be used in LED lighting applications.

What is the working principle of diode?

The most common function of a diode is to allow an electric current to pass in one direction (called the diode’s forward direction), while blocking it in the opposite direction (the reverse direction). As such, the diode can be viewed as an electronic version of a check valve.

Why a PN junction has capacitance?

The depletion region of the p-n junction diode has high resistance. Hence, the depletion region acts like the dielectric or insulating material. Therefore, charge is stored at the depletion region in the form of electric field. The ability of a material to store electric charge is called capacitance.

Why is the p-n junction called a diode?

Since the p-n junction demonstrates such a unipolar (rectifying) response to the applied voltage it is called a p-n diode and is denoted in circuit diagrams as a following symbol: The current voltage (IV) characteristic for the diode is rectifying and is very different from that for a resistor.

Why do electrons move away from the p-n junction?

An applied voltage with the indicated polarity further impedes the flow of electrons across the junction. For conduction in the device, electrons from the N region must move to the junction and combine with holes in the P region. A reverse voltage drives the electrons awayfrom the junction, preventing conduction.

How does the PN junction in a semiconductor work?

After doping an intrinsic semiconductor material, usually silicon, so that part of it is p-type and the other part is n-type, a pn junction is formed at the boundary between the p and n regions. In the p region, the majority carriers are holes while in the n region, the majority carriers are free electrons.

Why are free electrons not moving to the positive terminal?

The free electrons from the negative terminal cannot move towards the positive terminal because the wide depletion region at the p-n junction resists or opposes the flow of free electrons. Cathode terminal or positive terminal supplies holes to the p-n junction.