Semiconductors are materials that have an electrical conductivity value that falls between the conductivity of conductors and insulators. They are essential for the operation of many electronic devices, such as transistors, diodes, and lasers.
There are two types of semiconductors: degenerate semiconductors and non-degenerate semiconductors. Degenerate semiconductors are semiconductors with a high level of doping, meaning that they have a large number of impurities added to them. This doping causes the Fermi level, which is the energy level at which the probability of finding an electron is 50%, to lie within the conduction band. This means that there are a large number of electrons in the conduction band, which makes the semiconductor behave more like a metal than a semiconductor.
Non-degenerate semiconductors, on the other hand, have a low level of doping. This means that the Fermi level lies in the bandgap, between the conduction band and the valence band. This means that there are only a small number of electrons in the conduction band, and the semiconductor behaves more like a traditional semiconductor.
In this blog post, we will discuss the key differences between degenerate semiconductors and non-degenerate semiconductors. We will also discuss the applications of each type of semiconductor.
- 1 What exactly are degenerate semiconductors? And why is it important to know them?
- 2 What exactly are non-degenerate semiconductors? How do they differ from degenerate ones?
- 3 Difference between Degenerate and Non-Degenerate Semiconductors
- 4 Advantages & Disadvantages of Degenerate Semiconductors
- 5 Advantages & Disadvantages of Non-Degenerate Semiconductors
What exactly are degenerate semiconductors? And why is it important to know them?
A degenerate semiconductor is a material that has a band gap smaller than its band gap energy. This means that these materials conduct electricity at lower temperatures compared to other semiconductors. Degenerate semiconductors are often used in high-power devices such as transistors.
Degenerate semiconductors are widely used in electronics due to their low-temperature coefficient of resistance (TCR), high breakdown voltage, and low dielectric constant. They also have wide applications in solar cells and optoelectronic devices.
What exactly are non-degenerate semiconductors? How do they differ from degenerate ones?
Non-degenerate semiconductors have no valence electrons in the highest occupied molecular orbital (HOMO), and therefore do not conduct electricity.
Non-degenerate semiconductor materials include silicon, gallium arsenide, germanium, indium phosphide, etc. They have lower concentrations of free carriers and thus higher resistances compared to degenerate semiconductors.
Difference between Degenerate and Non-Degenerate Semiconductors
|Degenerate Semiconductors||Non-Degenerate Semiconductors|
|A degenerate semiconductor is a semiconductor that has a band gap smaller than its equilibrium Fermi level.||In contrast to a degenerate semiconductor, a non-degenerate semiconducting material has a larger band gap than its equilibrium Fermí level.|
|Degenerate semiconductor refers to a material whose electron mobility decreases as temperature increases.||Non-Degenerate Semiconductors (NDS) are materials that have no band gap.|
|Degenerate semiconductors conduct electricity even at lower temperatures.||Non-Degenerate Semiconductors are not conductive at room temperature and they cannot conduct electricity.|
|Degenerate semiconductors have been widely applied in electronic devices due to their low resistivity at high temperatures.||Non-degenerate semiconductor materials are useful for making transistors and photodetectors.|
|N-Type & P-Type semiconductors are some examples of Degenerate semiconductors.||ZnO & BeO are some examples of Non-Degenerate Semiconductors.|
Advantages & Disadvantages of Degenerate Semiconductors
- High electron mobility
- Low resistivity (high conductance)
- High breakdown voltage
- Relatively high current density
- Good thermal stability
- Wide band gap
- High dielectric constant
- Easy fabrication
- Easily integrated into existing processes
- Low cost
- Excellent optoelectronic properties
- Poorly conducting materials
- Lower carrier mobilities than metals
- More difficult to integrate with Si
- Difficult to fabricate structures
- Limited device lifetimes
- High defect densities
- Not suitable for RF applications
- Cannot be used in CMOS circuits
- Very expensive
- Poor optical transparency
- May cause contamination issues
- It May have low reliability
Advantages & Disadvantages of Non-Degenerate Semiconductors
Non-degenerate semiconductor materials have been used in many industries due to their low cost, high performance, and wide applications. Here are some advantages of non-degenerate semiconductors:
- Low cost
- High performance
- Wide applications
- Easy processing
- Good compatibility
- Wide range of application
However, non-degenerate semiconductors have disadvantages too:
- Lower stability than degenerate semiconductors
- More difficult to fabricate compared to degenerate semiconductors (e.g., Si)
- Difficult to purify
- Less stable under extreme conditions
- Poor thermal conductivity
- Not suitable for ultra-high temperature (UHT) packaging
- Limited choice of material
- Cannot be recycled