Question: What Is The PN Junction Theory?

What is pn junction how it is formed?

P-n junctions are formed by joining n-type and p-type semiconductor materials, as shown below.

Since the n-type region has a high electron concentration and the p-type a high hole concentration, electrons diffuse from the n-type side to the p-type side..

What is the importance of pn junction?

It is used for many forms of rectification for current levels both large and small, as well as high and low voltage levels, and this semiconductor device finds many uses in all manner of electronic circuit designs. The PN junction has the very useful property that electrons are only able to flow in one direction.

What causes the depletion region?

The depletion layer in P-N junction region is caused by Due to the larger concentration of electrons in N-side and holes in P-side, they diffuses from their own side to other side. Hence depletion region produces.

How does a diode actually work?

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.

How do pn junctions work?

PN junction is formed in a single crystal by joining two N-type and P-type semiconductors. … When the junction diode is biased in the reverse direction, the majority charge carriers are attracted by the respective terminals away from the PN junction, thus avoiding the diffusion of electrons and holes at the junction.

What is pn junction and its characteristics?

A PN Junction Diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. … By applying a negative voltage (reverse bias) results in the free charges being pulled away from the junction resulting in the depletion layer width being increased.

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. … A Schottky junction is a special case of a p–n junction, where metal serves the role of the p-type semiconductor.

What is pn junction with diagram?

As a result, the charge density of the P-type along the junction is filled with negatively charged acceptor ions ( NA ), and the charge density of the N-type along the junction becomes positive. … This charge transfer of electrons and holes across the PN junction is known as diffusion.

What is the use of Zener diode?

Zener diodes are used for voltage regulation, as reference elements, surge suppressors, and in switching applications and clipper circuits. The load voltage equals breakdown voltage VZ of the diode. The series resistor limits the current through the diode and drops the excess voltage when the diode is conducting.

What is P type material?

A p-type semiconductor is a type of semiconductor. … A p-type semiconductor has more holes than electrons. This allows the current to flow along the material from hole to hole but only in one direction. Semiconductors are most often made from silicon. Silicon is an element with four electrons in its outer shell.

What is meant by photodiode?

A photodiode is a semiconductor device that converts light into an electrical current. The current is generated when photons are absorbed in the photodiode. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas.

Why depletion layer is formed?

Depletion Region When a p-n junction is formed, some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions. In so doing they leave behind positive ions at the donor impurity sites.

How is a diode formed?

A diode is formed by joining two equivalently doped P-Type and N-Type semiconductor. … Causing a small region of the N-type near the junction to lose electrons and behaves like intrinsic semiconductor material, in the P-type a small region gets filled up by holes and behaves like an intrinsic semiconductor.

Why pn junction is called diode?

A p-n junction diode is two-terminal or two-electrode semiconductor device, which allows the electric current in only one direction while blocks the electric current in opposite or reverse direction. … The p-n junction, which is formed when the p-type and n-type semiconductors are joined, is called as p-n junction diode.

What do you mean by depletion region?

[ dĭ-plē′shən ] A region in a semiconductor device, usually at the juncture of P-type and N-type materials, in which there is neither an excess of electrons nor of holes. Large depletion regions inhibit current flow.

What is knee voltage?

In the forward region of the graph, the voltage at which the current starts to increase quickly is called the knee voltage of the diode. Study of a diode circuit usually comes down to determining if the diode voltage is higher or lower than the knee voltage.