In today’s technological era, semiconductors are an indispensable component. From smartphones to computers, semiconductors are the building blocks. Without them, our world as we know it today would not exist.
Updated on 3 Sep 2024, 9:44 PM
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Extrinsic Semiconductor vs. Intrinsic Semiconductor
| Intrinsic semiconductor | Extrinsic semiconductor | |
| 1. | It is pure semiconductor (without doping) | Intentionally doped with specific impurities or dopants. |
| 2. | conductivity is low. | conductivity is high. |
| 3. | conductivity depends on temperature only. | conductivity depends on added impurities and temperature. |
| 4. | free electrons and holes are equal in number | number of free electrons and holes are not equal |
| 5. | Examples: pure crystal lattice of silicon (Si) and germanium (Ge) | Examples: p-type and n-type |
What is Semiconductor?
A semiconductor is a crystalline solid that has a specific electrical property, whose conductivity value is more than an insulator and less than of a conductor.
There are two types of charge carriers in semiconductors: electrons and holes (absence of electrons)
The electrical conductivity of the semiconductors increases with increasing temperature as the resistance decreases, allowing electrons to move easily from the valance band to the conductive band.
Intrinsic Semiconductor
Intrinsic semiconductor is a pure semiconductor crystal without any intentionally doped impurities.
It is also known as pure semiconductor or undoped semiconductor.
In intrinsic semiconductors, the number of free electrons is equal to the number of holes.
Ex: Si (most used, because of higher melting point) and Ge
Fig: Pure semiconductor crystal; source: NCERT
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Extrinsic Semiconductor
An extrinsic semiconductor is an impure semiconductor that has been intentionally modified by adding specific impurities to the pure semiconductor crystal lattice.
It is also known as an impurity semiconductor or doped semiconductor.
Dopants or impurities are –
Trivalent atoms: Boron(B), Aluminium(Al), Indium(In)
Pentavalent atom: Phosphorus(P), Arsenic(As), Antimony(Sb)
p type Semiconductor
- It is created by doping a pure semiconductor crystal lattice with a trivalent molecule (impurity).
- Impurities/Dopants: Boron(B), Aluminium(Al), Indium(In)
- In a p-type semiconductor, holes serve as the charge carriers.
- It is used to create p-n junction for making devices like transistors and diodes.
Fig: p-type semiconductor; source: NCERT
n type Semiconductor
- n-type semiconductor is created by doping a pure semiconductor crystal with a pentavalent molecule (impurity).
- Dopants: Phosphorus(P), Arsenic(As), Antimony(Sb)
- In a n-type semiconductor, electrons serve as the charge carriers.
- It is also used to create p-n junction for making devices like transistors and diodes.
Fig: n-type semiconductor; source: NCERT
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