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

[Naveeddd]

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

 

[Davide86]

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.

 

[DrDu]

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.

 

[Naveeddd]

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?

 

[Naveeddd]

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?

 

[DrDu]

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.