Three different electron configurations in a semiconductor

In summary, the conversation discusses three different electron configurations in a semiconductor and their respective conductivities. The middle configuration has lower conductivity compared to the other two, despite still being able to conduct. The author mentions that a higher number of electrons near the Fermi surface leads to better conductivity, and also suggests that configuration 2 has a smaller Fermi surface and a larger effective mass. The speaker also asks about finding an expression for conductance and other parameters to consider.
  • #1
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Attached is a picture of three different electron configurations in a semiconductor. It seems from the author of my book that it should be obvious that the middle one has a lot lower conductivity than the 2 other. Why is that? I mean it is possible for the electrons to move in the conduction band and holes to move in the valence band for this configuration so it is not that it is nonconducting - it just low compared to the other configuration. How do you quantitatively find an expression for the conductance or what parameters should I at least be looking at other than the electron density which is lowest in the first picture (but this configuration still conducts a lot better!).
 

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  • #2
In general, many electrons close to the Fermi surface lead to a better conductivity. Configuration 2 has the smallest Fermi surface. And then you also have a larger effective mass, I think.
 

1. What is a semiconductor?

A semiconductor is a material that has properties between those of a conductor and an insulator. This means it can conduct electricity, but not as well as a metal, and can also act as an insulator, blocking the flow of electricity.

2. What are the three different electron configurations in a semiconductor?

The three different electron configurations in a semiconductor are the valence band, the conduction band, and the band gap. The valence band contains electrons that are tightly bound to atoms and cannot move freely. The conduction band contains electrons that are able to move freely and conduct electricity. The band gap is the energy gap between the valence and conduction bands.

3. How do these electron configurations affect the conductivity of a semiconductor?

The band gap determines the conductivity of a semiconductor. If the band gap is small, electrons can easily move from the valence band to the conduction band, making the semiconductor a good conductor. If the band gap is large, electrons have a harder time moving, making the semiconductor a poor conductor.

4. What is the role of dopants in creating different electron configurations in a semiconductor?

Dopants are impurities that are intentionally added to a semiconductor to alter its electronic properties. They can either donate or accept electrons, creating an excess or deficiency in the number of electrons in the semiconductor, which affects the band gap and electron configurations.

5. How are these electron configurations utilized in electronic devices?

The different electron configurations in a semiconductor are utilized in electronic devices to control the flow of electricity. By manipulating the band gap, researchers can create transistors, diodes, and other electronic components that are essential in modern technology.

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