How is the Fermi Level Formed in Compound Semiconductors Like GaN and GaAs?

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Discussion Overview

The discussion revolves around the formation of the Fermi level in compound semiconductors such as GaN and GaAs. Participants explore theoretical aspects, definitions, and calculations related to the Fermi level in these materials.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that the Fermi level is traditionally defined for metals due to half-filled bands, while it is commonly stated that it lies at the midpoint of the band gap in semiconductors.
  • Others clarify that the Fermi level is the chemical potential of electrons at absolute zero (T=0K) and is well-defined even in semiconductors and insulators.
  • One participant expresses confusion about how to determine the Fermi level in GaN and Ce-doped GaN, questioning the notion of it being in the middle of the band gap given the absence of energy levels.
  • Another participant suggests that the Fermi level is not necessarily at the midpoint of the band gap but rather somewhere within it, explaining that the alignment of chemical potentials between a metal and semiconductor prevents electron flow.
  • There are inquiries about calculating the specific value of the Fermi level in GaN.

Areas of Agreement / Disagreement

Participants express differing views on the definition and positioning of the Fermi level in semiconductors, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

There are unresolved questions regarding the calculation of the Fermi level in specific materials and the implications of its position within the band gap.

Who May Find This Useful

Readers interested in semiconductor physics, particularly those studying the properties of compound semiconductors like GaN and GaAs, may find this discussion relevant.

Naveeddd
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Aasslam u alaikum to all,
i have confusion in knowing that " how fermi level form in a compound semiconductors e.g GaN, GaAs, etc.
Thanks to all
 
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Strictly speaking the fermi level can be defined only in metals, because of the condition of half-filled bands. However usually it is said that the fermi level in the semiconductors lies at the half of the band gap; this fact is reported in every introductory solid state test. Maybe in one of these books you can also find a plausible explanation about.
 
This question should be a FAQ, maybe you search for older threads.
The Fermi level is the chemical potential of the electrons at T=0K. So it is well defined even for semi-conductors and isolators.
 
Davide86 said:
Strictly speaking the fermi level can be defined only in metals, because of the condition of half-filled bands. However usually it is said that the fermi level in the semiconductors lies at the half of the band gap; this fact is reported in every introductory solid state test. Maybe in one of these books you can also find a plausible explanation about.
thank you for help.
but i have stil confusiuns that how i can find value of fermi level in GaN and later in Ce doped GaN.
how does fermi level can lei in mid of the band gap? as there are no number of energy levels?
 
DrDu said:
This question should be a FAQ, maybe you search for older threads.
The Fermi level is the chemical potential of the electrons at T=0K. So it is well defined even for semi-conductors and isolators.
thanks
can u calculate the value of fermi level in "GaN" a compound semeconductor?
 
usually, it is not in the mid of the band gap but only somewhere in the band gap.
You can imagine as follows: When you bring a metal in contact with your semiconductor, then no electrons will flow from the semiconductor to the metal or vice verse if the chemical potential of the metal coincides with that of the semiconductor. Then you take the mimit T to 0. I suppose it can be calculated from temperature greens functions.
 

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