There are mainly two types of semiconductor. These two types of semiconductors are Intrinsic Semiconductor and Extrinsic Semiconductor. Extrinsic Semiconductors can be further divided into two parts. Types of semiconductors will be discussed in detail in this article.
What is a Semiconductor?
Substances whose electrical conductivity is between conductor and insulator are called semiconductors. Semiconductors can be defined in another way; those substances through which electricity cannot flow at normal temperatures, but an increase in electric current as of the temperature rises, are called semiconductors. At normal temperatures, all these semiconductor materials are like insulators.
That is, no electricity can flow through a semiconductor at normal temperature; all those substances are called semiconductors. At normal room temperature, a semiconductor contains a small number of free electrons, which can cause very small amounts of electricity to flow through the semiconductor.
According to the definition of energy band, the valence band of semiconductor material is almost full, and the conduction band is almost empty. And the amount of energy gap between the valence band and the conduction band is very small. As the temperature in the semiconductor material increases, the amount of energy gap between the valence band and the conduction band decreases. And when a small amount of electric field is applied, the electrons are transferred from the valence band to the conduction band.
List of semiconductor materials
When electricity flows in any part of semiconductor material, a small part of it spreads to other places. This type of semiconductor has 4 electrons in its outer orbit. And its resistance ranges from 10 ^ -4 to .5 ohm-meters.
The semiconductor substances are-
- Silicon carbide
- Gallium arsenide is currently being used as a semiconductor for various purposes.
Types of Semiconductor Devices
Just as a device is made up of many parts, so are semiconductor devices made of different semiconductor components.
We need to remember that semiconductor devices and components are not one thing. However, some semiconductor components can be called semiconductor devices. E.g., Transistor.
A complete semiconductor device is made of different types of semiconductor components. There are many types of semiconductor components. Some components are of two terminals, and some components are of three terminals. We have presented the two-terminal and three-terminal components separately here.
Two terminal Semiconductor components
- rectifier diode
- Gunn diode
- IMPATT diode
- Laser diode
- LED(Light-emitting diode)
- PIN diode
- Schottky diode
- Transient voltage suppression diode
- Tunnel diode
- Zener diode
- Zen diode
- Photo transistor
- Solar cell
- LDR (Light Dependent Resistor)
- VCSEL (Vertical cavity surface emitting laser)
Three terminal Semiconductor devices/components
- Bipolar Transistor(PNP & NPN)
- Unipolar Transistor(FET & MOSFET)
- Field Effect Transistor(FET)
- Metal Oxide Field Effect Transistor(MOSFET)
2.Silicon Controlled Rectifier (SCR)
Four terminal Semiconductor devices:
1.Hall effect sensor (magnetic field sensor)
Type of semiconductor
There are mainly two types of semiconductors.
- Intrinsic Semiconductor
- Extrinsic semiconductor
Extrinsic semiconductor can again be divided into two parts.
- N type semiconductor
- P type semiconductor
Intrinsic Semiconductor definition
Pure semiconductors are basically called silicon and germanium. Because they do not contain any waste or any other element, the semiconductor behaves like a non-conductive at a temperature of zero degrees Celsius. If the temperature in the semiconductor is increased, the electrons in their valence band exceed the conduction band, for which the value of the resistance of the semiconductor decreases. As a result, the intrinsic semiconductor behaves like a partial conductor. The energy gap between the valence band and the conduction band of silicon is 1.1 electron volts. And the energy gap between the valence band and the conduction band of germanium is .7 electron volts.
The energy gap between the valence band and the conduction band of the intrinsic semiconductor is much smaller. For this, the electron conduction band of the valence band of the intrinsic semiconductor at room temperature can go. The transfer of electrons from the valence band to the conduction band results in the formation of a positive charge in the valence band and creates a hole. For this, we can say that the hole always displays a positive charge.
We all know that Intrinsic Semiconductor does not conduct electricity at a temperature of zero degrees Celsius. And as the temperature increases, the electrons in the valence band begin to transfer to the conduction band. A small amount of electricity can flow through the intrinsic semiconductor at room temperature.
Let’s see how electricity flows through the intrinsic semiconductor at room temperature:
When a semiconductor is carried above a temperature of zero degrees Celsius, the electrons in the valence band absorb the temperature. Absorption of temperature causes excitation in electrons. At one stage of the excitation, the electrons in the valence band begin to transfer to the conduction band. At room temperature, some amount of electrons move into the conduction band.
When a high-temperature electric field is applied to the semiconductor, it is observed that the electrons of the conduction band go to the anode, and the holes of the valence band go to the cathode. Thus it is seen that electricity flows through the semiconductor through the participation of both the hole and the electron of the semiconductor. Due to these reasons, electricity flows through the semiconductor.
Extrinsic Semiconductor definition
An extrinsic semiconductor is made by mixing an appropriate amount of any product and any other substance as an adulterant. The most commonly used intrinsic semiconductor is –
- Elements with five valence electrons
- An element with three valence electrons
The five constituent elements are arsenic, antimony, phosphorus.
The three constituent elements are gallium, aluminum, boron, and indium.
Atoms that have five electrons in their last orbit are called donor atoms. This is because the conduction band of pure germanium donates an electron. Atoms that have three electrons in their last orbit are called receptive atoms because it takes an electron from the germanium atom.
Extrinsic semiconductors are divided into two parts based on adulterated materials.
- p type semiconductor
- n type semiconductor
P-type semiconductor definition:
When a triangular atom is attached to pure silicon or germanium atom as a waste, its three valence electrons form a covalent bond by sharing the valence electrons of three nearby silicon. But its valence cannot form a bond with the fourth silicon due to the lack of electrons. The result is the creation of a hole. Thus, the combination of each triangular atom creates a hole. The new semiconductor formed to carry this positive hole charge is called P-type semiconductor.
More doping results in more holes originating. Therefore the majority charge carrier of P-type semiconductor is the hole, and the minority charge is an electron. The triangular atom is called the receptor atom. This is because each hole receives one electron during recombination. Such acceptor atoms are aluminum, boron, and gallium.
N-type semiconductor definition:
When a five-composite atom of pure silicon crystal is inserted as an adulterant, then the four electrons of the five covalent atoms form a covalent bond by sharing the valence electrons of the nearest four silicon atoms. And completes its valence band by eight electrons. As a result, an extra electron is released from the atom with five valances. This free electron then moves to the conduction band.
In this way, the electrons of the conduction band can be increased by increasing the amount of doping. As a result, electrons become the majority charge carriers. On the other hand, the amount of holes produced under thermal energy becomes negligible. Since electrons carry a negative charge, a semiconductor formed in this way is called an N-type semiconductor. An atom with five components is called a donor atom. This is because they generate electrons in the conduction band. These donor atoms are arsenic, antimony, and phosphorus.
Read More: N-type VS P-type Semiconductor Difference
Conclusion of types of semiconductor
From this article, we learned in detail about the classification of semiconductors. We hope you have read this post to know more about semiconductor classification. If you have any questions, please comment and don’t forget to share it with friends. Learn about electrical & electronics and stay with electrotricks.
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- “18.104.22.168 The “hot-probe” experiment”. ecee.colorado.edu. Retrieved 27 November 2020.
- Shockley, William (1950). Electrons and holes in semiconductors : with applications to transistor electronics. R. E. Krieger Pub. Co. ISBN 978-0-88275-382-9.