What is n and p-type semiconductor?


What is n and p-type semiconductor?


n and p-type semiconductors are extrinsic semiconductors. A detailed explanation of n and p-type semiconductors is given below.



A semiconductor is a type of material that has electrical conductivity levels between that of a conductor (such as most metals) and an insulator (like ceramic). Semiconductors can conduct electricity under certain conditions, making them essential for modern electronics. Their ability to conduct electricity can be greatly affected by factors such as impurities added to the material (a process known as doping), the application of electric fields, exposure to light, and temperature changes.

Extrinsic Semiconductor:

An extrinsic semiconductor is a type of semiconductor that has had impurities intentionally added to it to modify its electrical properties. This process, known as doping, involves adding a small amount of a foreign element to the intrinsic (pure) semiconductor material, typically silicon or germanium. The added impurities are called dopants.

Doping drastically changes the conductivity of the semiconductor by introducing free-charge carriers. There are two types of extrinsic semiconductors based on the type of charge carriers they predominantly support:

  1. N-type Semiconductors: These are created by doping the semiconductor with an element that has more valence electrons than the semiconductor material. For example, doping silicon with phosphorus (which has five valence electrons compared to silicon’s four) adds extra electrons, which are the majority carriers, to the material. The extra, loosely bound electrons increase the conductivity of the semiconductor.
  2. P-type Semiconductors: These result from doping the semiconductor with an element that has fewer valence electrons than the semiconductor material. For instance, doping silicon with boron (which has three valence electrons) creates “holes” or places where an electron is absent. These holes can accept electrons, making them the majority carriers. The movement of holes effectively increases the conductivity.

Summary: n and p-type semiconductor

P-type Semiconductor:

  1. A p-type semiconductor is formed by introducing impurities such as boron or indium into an intrinsic semiconductor material. This process is also known as doping.
  2. In p-type semiconductors, the holes are the majority carriers, and electrons are the minority carriers.
  3. In a p-type semiconductor, the concentration of holes is significantly higher than that of electrons.
  4. The energy level of the acceptor in the p-type is close to the valence bond and far from the conduction band.

n-type Semiconductor:

  1. An n-type semiconductor is created by doping an intrinsic semiconductor with impurities such as phosphorus or antimony.
  2. In n-type semiconductors, electrons are the majority charge carriers, and holes are the minority charge carriers.
  3. In n-type semiconductors, the concentration of electrons exceeds that of holes.
  4. The energy level of the donor atom in n-type is closer to the conduction band than the valence band.

Q1. The Forbidden Energy Gap for Germanium is:
Q2. An n-type Semiconductor is_________

Q3. Leakage Current in the Silicon Semiconductor is in the order of ____

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