Fermi level change in semiconductors

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SUMMARY

The discussion centers on the impact of substituting silicon (Si) with germanium (Ge) in a doped semiconductor lattice, specifically regarding the acceptor energy levels of boron dopants. It is established that the acceptor level does depend on the semiconductor base due to variations in band structure and interatomic spacing. The band gap of silicon is approximately twice that of germanium, influencing the energy levels of holes. A notable reference is made to a 2003 paper that discusses hydrogen's universal energy level in relation to semiconductor band gaps aligned with the vacuum level.

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  • Understanding of semiconductor physics, specifically band structure
  • Knowledge of doping mechanisms in semiconductors
  • Familiarity with energy levels and band gaps in materials
  • Basic principles of solid-state theory
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  • Research the band structure differences between silicon and germanium
  • Explore the effects of interatomic spacing on semiconductor properties
  • Study the concept of universal energy levels in semiconductors
  • Read the 2003 paper on hydrogen's energy level in relation to semiconductor band gaps
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Researchers, materials scientists, and electrical engineers interested in semiconductor physics, particularly those focusing on doping effects and energy level manipulation in semiconductor materials.

Helena Wells
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TL;DR
Does the acceptor level or donor level change if we change the base of the semiconductor?
Suppose we have a crystal lattice of doped Si with dopant Boron atoms. The energy level of the holes of the Boron atoms are just some eV above the valence band of Si.

My question: If we replace all the Si atoms with Ge atoms will the acceptor level change or not? I don't think it will change but why not ask it? In other words, does the acceptor level depend on the type of semiconductor we use as base?
 
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The band structure is a product of the crystal structure (which reflects the structure of the base) as well as the interatomic spacing. The band gap for Silicon is twice that of Germanium and so yes it does depend. I believe the most important effect is the interatomic distance, but don't quote me..
 
So will it be higher or lower?Is there a general rule for it?
 
hutchphd said:
The band structure is a product of the crystal structure (which reflects the structure of the base) as well as the interatomic spacing. The band gap for Silicon is twice that of Germanium and so yes it does depend. I believe the most important effect is the interatomic distance, but don't quote me..
@hutchphd what are you studying/have you studied?
 
Long ago I did solid state theory...mostly surfaces and scattering from surfaces. I am now retired after doing optical, electronic, and systems design mostly for medical devices for 25 years . Also folks would occasionally hire me just for another novel look at a problem. I am a better engineer than I am a physicist...but I do love knowing the physics.
 
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Helena Wells said:
So will it be higher or lower?Is there a general rule for it?

I do not believe there is a general rule of thumb. Especially in complex compund semiconductors (like oxides and nitrides).
However in 2003, it was shown that hydrogen has a universal energy level provided that the band gap of the semiconductor is aligned according to unified scale (for example aligned with respect to vacuum level).

This is the paper that pointed this out:
https://www.nature.com/articles/nature01665
 
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