What is a non-degenerate semiconductor? It is a question that may not pop into your head on a daily basis, but it is an important one to understand. A semiconductor is a material that can connect and conduct electricity under certain conditions. 

To control the properties of the semiconductor material, impurities are often added. When these impurities are added, they can change the way the semiconductor conducts electricity. Depending on the number of impurity atoms, they are categorized as degenerate or non-degenerate. In this post, we will take a look at non-degenerate semiconductors and their advantages.

What Are Degenerate And Non-Degenerate Semiconductors?

Semiconductors are materials that have been specifically designed to be used in electronic devices and circuits. They are made of materials like carbon, silicon, germanium, and silicon-germanium, which have been doped with impurities to create either n-type or p-type semiconductors. N-type semiconductors are made by doping the material with an element like phosphorus, while p-type semiconductors are made by doping the material with an element like boron.  

Degenerate semiconductors are those in which the doping concentration is high enough that the impurity energy levels are very close together. In degenerate semiconductors, there is very little space between the valence band edge and the conduction band edge. Non-degenerate semiconductors are those in which the doping concentration is not high enough to cause the impurity band levels to be close together. In non-degenerate semiconductors, there is a larger gap between the valence band and the conduction band.

Degenerate Semiconductors

As mentioned above, degenerate semiconductors are those in which the doping concentration is high enough that the impurity energy levels are very close together. The most common type of degenerate semiconductor is silicon, which has a doping level of 10^16 atoms/cm^3. other examples of degenerate semiconductors include germanium and silicon-germanium alloys. Because of the high level of doping, degenerate semiconductors act more like metals than semiconductors.

Non-Degenerate Semiconductors

Non-degenerate semiconductors are those in which the doping concentration is not high enough to cause the impurity energy levels to be close together. Because the level of doping is not as high, these types of semiconductors still maintain the properties of a semiconductor. Non-degenerate semiconductors are used in solar cells, light-emitting diodes, and many other electronic devices.

Properties Of A Non-Degenerate Semiconductor

Let’s take a look at the basic properties of a non-degenerate semiconductor. A non-degenerate semiconductor is a material in which the levels of the conduction and valence bands are not close together in energy. This results in a material with a large band gap. The band gap is the forbidden energy gap between the valence band and the conduction band. This gives the semiconductor its unique properties. To learn more about the energy levels of a semiconductor, read this article.

Electron Mobility

One of the most important properties of a semiconductor is its electron mobility. Electron mobility is a measure of how easily electrons can move through a material. In general, materials with high electron mobility are better conductors than materials with low electron mobility.

Electron mobility is affected by both the band structure of the material and defects in the crystal lattice. The band structure determines how many states are available for electrons to occupy and how close together these states are in energy. Defects in the crystal lattice act as scattering centers, which impede the flow of electrons through the material. Both n-type and p-type semiconductors have high electron mobilities.

Holes Mobility

In a non-degenerate semiconductor, there are no states available for holes in the valence band (holes are simply vacant electron states). However, there are always some thermally excited electrons in the conduction band. These thermally excited electrons can recombine with holes that are created by doping or by thermal excitation from the valence band. 

The intrinsic carrier concentration decreases with increasing temperature while donor concentration usually remains constant over a certain temperature range. As temperature increases, more electrons are thermally excited into the conduction band which results in an increase in hole density. At very high temperatures, however, dopant atoms begin to ionize which decreases hole concentration despite an increase in thermal excitation. 

Non-degenerate semiconductors have large band gaps and high electron mobilities. Holes are created by doping or thermal excitation and their concentrations increase with temperature up to a point where dopant atoms begin to ionize. Knowing these properties is essential to understanding how semiconductors work and how they can be used in various electronic devices.

Applications Of Non-degenerate Semiconductors

You may not realize it, but non-degenerate semiconductors are all around you. From the light-emitting diodes in your TV to the solar panels that power your home, these materials have a wide range of applications. We’ll explore some of the more common uses for non-degenerate semiconductors.

Solar Cells

One of the most common applications for non-degenerate semiconductors is solar panels. Solar panels rely on the photovoltaic effect to convert sunlight into electrical energy. This process requires a material with a broad absorption spectrum, which non-degenerate semiconductors such as silicon (Si) and germanium (Ge) have. In fact, Si solar cells are currently the most popular type of solar cell in the market.

LEDs

Another common use for non-degenerate semiconductors is light-emitting diodes (LEDs). LEDs are used in a wide variety of applications, from electronic displays to automotive taillights. The basic principle behind an LED is that when an electric current is passed through a material like silicon carbide (SiC), it emits light. This effect can be harnessed to create very bright, and efficient lights with a long lifespan.

Microwave Ovens

Non-degenerate semiconductors are also used in microwave ovens. Microwave ovens work by firing microwaves (a type of electromagnetic radiation) into food to heat it up. The frequency of microwaves emitted by an oven is determined by the material used in its cavity. The semiconductor material used in microwave ovens has a very high melting point and does not break down at high temperatures.

Smartphone Cameras

One of the most common applications of non-degenerate semiconductors is in smartphone cameras. The image sensor in your camera phone contains an array of these materials that are sensitive to light. When light hits these sensors, it generates an electrical current that is used to create the image you see on your screen.

Advantages And Disadvantages Of Non-degenerate Semiconductors

Non-degenerate semiconductors have both advantages and disadvantages. So, what are the advantages of non-degenerate semiconductors?

Advantages

1. Non-degenerate semiconductors have a higher thermal conductivity than degenerate semiconductors. This is because the lattice vibrations are not hindered by the extra electrons. 
2. They also have a higher electrical conductivity than degenerate semiconductors. This is because there are more carriers available for conduction. 
3. They can be used at higher temperatures than degenerate semiconductors. 
4. The performance of transistors is not affected by temperature changes as much as it is in degenerate semiconductors.

Disadvantages

1. Non-degenerate semiconductors have lower electron mobility than degenerate ones.  
2. They also have lower hole mobility than degenerate semiconductors. This is because the extra holes scatter phonons more readily. 
3. The on/off current ratio of transistors is lower in non-degenerate semiconductors than in degenerate ones.

Overall, non-degenerate semiconductors have both advantages and disadvantages when compared to degenerate semiconductors. The main advantage is that they offer more efficient conduction of electricity due to the fact that the accessible energy states are not equal in energy. However, the disadvantage is that they can be more difficult to control because the energy states are not equal. When deciding whether or not to use a non-degenerate or degenerate semiconductor, it is important to weigh the pros and cons carefully to ensure that you choose the right type of semiconductor for your needs.

FAQs

What Is A Degenerate Semiconductor Used For?

A degenerate semiconductor is a material that has been intentionally doped with impurities to increase its electrical conductivity. It is typically used in high-power applications where standard semiconductors would be unable to handle the high currents. Degenerate semiconductors are also sometimes used in optical devices, such as lasers and light-emitting diodes (LEDs), where they can generate more photons than a regular semiconductor.

Who Is The Global Leader In Semiconductors?

On a global scale, the top semiconductor technology companies are Samsung from South Korea, Semiconductor Manufacturing International Corporation in China, and Taiwan Semiconductor Manufacturing Corporation in Taiwan. These three powerhouses stand out as industry leaders for their cutting-edge technologies.