Accessing electrons from the Fermi Sea?

In summary, the conversation revolved around the possibility of using electrons from the Fermi sea in semiconductor materials as an electron source. It was mentioned that this is already being done in devices such as transistors, solar cells, and photoresistors. The discussion also touched on the use of semiconductors in high-QE photocathodes and how this has been a known practice since the 1950s. The question of accessing electrons from the Fermi sea was deemed to be already happening in current technology.
  • #1
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Recently a few friends and I were discussing the Fermi sea.

One friend made the statement that if you could access the electrons from the Fermi Sea you could use the material you accessed them from as an electron source. Didn't make sense to me but it got me wondering.

My question is, What would it take? Why hasn't it been done/tried before?
 
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  • #2
Well, I am a little confused. The free electrons in a metal makes up the Fermi sea, and one can immediately use them as an electron source by shining light on the metal by photoemission.

Was this the question?
 
  • #3
Sorry, we were talking about removing them from a semiconductor material.

I know that in metals the conduction band and Fermi level overlaps, but in semiconductors there is a potential barrier that separates them.

My friend said if you could find a way to get those electrons across the barrier you could use the semiconductor as a separate electron source. Just got me thinking, perhaps there is a way you could really do this...?
 
  • #4
I'm not quite sure what you're getting at. Many semiconductor devices work on this exact principle. Examples include semiconductor transistors, solar cells, and photoresistors. Electrons are given enough energy to jump the band gap and go from the valence band to the conduction band.
 
  • #5
I'm confused also.

One of my area is high-QE photocathodes. All of the material (and I mean ALL) that we use to make these high-QE photocathodes are semiconductors. And we are using light sources to get those electrons in the valence band of the material.

And this is nothing new. Material such as the antimonides (eg: CsKSb, etc.) have been used in phototubes since the 50's.

So yes, we HAVE been "accessing electrons from the Fermi sea".

Zz.
 

1. How do electrons become accessible from the Fermi Sea?

The electrons in the Fermi Sea are inherently accessible due to their high energy levels. However, in order to access them for experimental purposes, an external stimulus such as an electric field or light must be used to excite them and bring them to an even higher energy level.

2. What is the significance of accessing electrons from the Fermi Sea?

Accessing electrons from the Fermi Sea is crucial in understanding the behavior and properties of materials. The electrons in the Fermi Sea play a key role in determining the electrical, magnetic, and thermal properties of materials and studying them can provide insight into various physical phenomena.

3. Can electrons be accessed from the Fermi Sea in all materials?

No, not all materials have a Fermi Sea. Only materials with a Fermi energy level, such as metals, semiconductors, and some insulators, have a Fermi Sea of electrons. Materials without a Fermi Sea, such as non-conductive materials, do not have accessible electrons in this manner.

4. How is the energy of the accessed electrons from the Fermi Sea measured?

The energy of the accessed electrons is measured using various experimental techniques such as photoemission spectroscopy, tunneling spectroscopy, and scanning tunneling microscopy. These methods involve exciting the electrons and measuring the resulting energy changes to determine their energy levels.

5. Are there any potential risks in accessing electrons from the Fermi Sea?

There are no direct risks in accessing electrons from the Fermi Sea. However, the experimental techniques used to access them may involve high voltages, intense light sources, or other potentially hazardous materials. Proper safety precautions must be taken when conducting these experiments.

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