The Key Differences between Intrinsic and Extrinsic Semiconductors
Semiconductors are an essential component of the electronic devices that we use daily. Whether it’s a smartphone, computer, television, or a car, semiconductors play an integral role in powering these devices. Semiconductors can be classified into two types: intrinsic and extrinsic. In this article, we will discuss the key differences between intrinsic and extrinsic semiconductors.
What is an Intrinsic Semiconductor?
An intrinsic semiconductor material is a pure form of semiconductor material that has no impurities or doping agents added to it. It is made up of a single element such as silicon or germanium, which has four valence electrons in its outermost shell. In an intrinsic semiconductor, the number of free electrons is equal to the number of holes, and hence, there is no net current in the material. However, when an intrinsic semiconductor material is subjected to a thermal or light energy source, some of the covalent bonds between the electrons in the valence band break, leaving behind some free electrons and holes.
What is an Extrinsic Semiconductor?
An extrinsic semiconductor, on the other hand, is a semiconductor material that has impurities added to it to modify its electrical properties. This process is called doping, and it is typically achieved by adding small amounts of dopants to the semiconductor material. The dopants can either be electrons donors or acceptors. The most common dopants used in extrinsic semiconductors are boron, phosphorus, and arsenic. When these impurities are added, they create an excess of free electrons or holes in the material, making it either a p-type or n-type semiconductor.
Key Differences between Intrinsic and Extrinsic Semiconductors
The major differences between intrinsic and extrinsic semiconductors are:
– Purity: Intrinsic semiconductors are pure in nature, whereas extrinsic semiconductors have impurities added to them.
– Electrical conductivity: Intrinsic semiconductors have low electrical conductivity since they have an equal number of free electrons and holes, whereas extrinsic semiconductors have high electrical conductivity due to the added impurities.
– Doping: Intrinsic semiconductors are not doped, whereas extrinsic semiconductors are doped to create p-type or n-type semiconductors.
– Energy bandgap: The energy bandgap of intrinsic semiconductors is high, making it harder for electrons to jump from the valence band to the conduction band. In extrinsic semiconductors, the energy bandgap is lower, making it easier for electrons to jump from the valence band to the conduction band.
Conclusion
In conclusion, intrinsic semiconductors are pure forms of semiconductor materials, while extrinsic semiconductors are doped with impurities to create p-type or n-type semiconductors with higher electrical conductivity. Understanding the differences between intrinsic and extrinsic semiconductors is essential for designing and fabricating high-performance electronic devices that we use every day.
Table difference between intrinsic and extrinsic semiconductor
| Property | Intrinsic Semiconductor | Extrinsic Semiconductor |
|---|---|---|
| Doping | Undoped or pure semiconductor material | Doped with impurities to alter its electrical properties |
| Conductivity | Dependent on temperature and minority carrier concentration | Largely dependent on the type and concentration of impurities |
| Energy Bandgap | Narrow bandgap | Wide bandgap |
| Application | Used in electronic devices such as diodes, transistors, and solar cells | Used in electronic devices such as MOSFETs, LEDs, and laser diodes |