Name: Energy Band Gap
Uploaded: 2019-07-19
Duration: 5 min 21 s
Description: We know that certain materials conduct electricity whereas some don’t. Has it got anything to do with their energy bandgap? Let’s find out in this video.

Question

Define

N

and

P -

type semiconductors. Explain the working of

P - N

junction diode with circuit diagram in forward bias and reverse bias.

Accepted Answer

N-type Semiconductor

An extrinsic semiconductor which has been doped with electron donor atoms is called an n-type semiconductor, because the majority of charge carriers in the crystal are negative electrons.

P-type Semiconductor

An extrinsic semiconductor which has been doped with electron acceptor atoms is called a p-type semiconductor. Crystal doped with group III elements is the p-type semiconductor. Radiation Dosimetry.

Working of P-N junction diode

A P-N junction diode is said to be forward biased when the positive terminal of a cell or battery is connected to the p-side of the junction and the negative terminal to the n side.

When diode is forward-biased the depletion region narrows and consequently, the potential barrier is lowered. This causes the majority charge carriers of each region to cross into the other region. The electrons travel from the n-side to the p-side and go to the positive terminal of the battery.

The holes that travel from the p-side to the n-side combine with the electrons injected into the n-region from the negative terminal of the battery. This way the diode conducts when forward-biased.

Reverse-biased pn junction diode

A pn-junction diode is said to be reverse biased when the positive terminal of a cell or battery is connected to the n-side of the junction and the negative terminal to the p-side.

When reverse biased, the depletion region widens and the potential barrier is increased. The polarity of the battery extracts the majority charge carriers of each region. The holes in the p-region from the electrons injected into the p-region from the negative terminal of the battery.

The electrons in the n-region go to the positive terminal of the battery. This way, the majority charge carrier concentration in each region decreases against the equilibrium values and the reverse biased junction diode has a high resistance.

Thus, the diffusion current across the junction becomes zero. Thus, the diode does not conduct when reverse biased and is said to be in a quiescent or non-conducting state i.e., it acts as an open switch.

Forward Bias:

Reverse Bias:

Define $N$ and $P -$ type semiconductors. Explain the working of $P - N$ junction diode with circuit diagram in forward bias and reverse bias.

Important Questions on Semiconductor Electronics: Materials, Devices and Simple Circuits

Learn and Prepare for any exam you want !

Define N and P-type semiconductors. Explain the working of P-N junction diode with circuit diagram in forward bias and reverse bias.

Important Questions on Semiconductor Electronics: Materials, Devices and Simple Circuits

Learn and Prepare for any exam you want !

Define $N$ and $P -$ type semiconductors. Explain the working of $P - N$ junction diode with circuit diagram in forward bias and reverse bias.