Effect of Doping on Fermi Energy

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SUMMARY

Doping a semiconductor alters the Fermi energy level, which can either increase or decrease depending on whether the semiconductor is n-type or p-type. In n-type semiconductors, the Fermi level shifts upwards towards the conduction band due to the increased probability of electron occupancy, while in p-type semiconductors, it shifts downwards towards the valence band. This behavior is explained by the Fermi-Dirac distribution function, which describes the occupancy probability of electrons as a function of energy and temperature.

PREREQUISITES
  • Understanding of Fermi-Dirac distribution function
  • Knowledge of semiconductor physics
  • Familiarity with n-type and p-type doping concepts
  • Basic principles of charge conservation in solid-state physics
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  • Study the Fermi-Dirac distribution function in detail
  • Explore the effects of temperature on semiconductor behavior
  • Investigate the role of doping concentrations in semiconductor applications
  • Learn about charge carrier dynamics in n-type and p-type semiconductors
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Effect of Doping on Fermi Energy...

I was wondering if anyone could give me a clear answer on why doping a semi conductor raises or lowers the fermi energy depending on n or p type semi conductors. There seem to be a few standard ways of explaining this, some to do with charge conservation or the requirement that the probability of occupation be half, but I havn't found one that seems clear to me, any help on this would be much appreciated.
 
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I also faced the same problem but later on found a satisfying answer.
The answer follows like this.
The electrons in solid follows fermi-diarac distribution function, which is a function of probability of occupancy Vs Energy of Electron. The function depends upon the absolute temperature and a constant called the fermi-level. So, given that the temperature remains constant, The only way we could account for the increased probability of finding the electron in the valence band in N-type semiconductor is to assume that the constant has now shifted, i.e. the fermi level has now increased i.e. moved towards the valence band. This is the reason for shifting of fermi level due to doping.

Tell me if you still need more explanation.
 

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