Fermi level rise up with raisng up the temperature

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Discussion Overview

The discussion revolves around the behavior of the Fermi level in extrinsic semiconductors as temperature increases, particularly in the presence of donor atoms. Participants explore the underlying mechanisms and implications of this phenomenon.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions why the Fermi level rises with increasing temperature in extrinsic semiconductors with donors present.
  • Another participant suggests that valence electrons in semiconductors are trapped and can move within their localized spots, but may not have enough energy to jump into adjacent holes, which could relate to the Fermi level behavior.
  • A different participant inquires about the density of states in extrinsic semiconductors, specifically whether there is a higher density of states below the Fermi level.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the reasons behind the rise of the Fermi level with temperature, and multiple viewpoints and questions remain unresolved.

Contextual Notes

The discussion includes assumptions about the behavior of electrons and the density of states, which are not fully explored or defined. There are also unresolved questions regarding the specific mechanisms at play.

montser
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Hi,
Im just wondering, why the fermi level rise up with raisng up the temperature when donors are present in Extrinsic semiconductor?

thanx
 
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montser said:
Hi,
Im just wondering, why the fermi level rise up with raisng up the temperature when donors are present in Extrinsic semiconductor?

thanx

If I understand your question correctly, perhaps this image is of interest.

Valence electrons in a semiconductor tend to get trapped into particular places and jump around within some type of "grid". The electrons can move around in their own little spot (and will do so with raising temperature) even though there may be a hole right beside them. Ie. they do not have enough energy to jump into the hole. Even if the electron has enough energy to jump into the hole beside it, the electron would leave a hole where the electron just jumped out of.
 


montser said:
Hi,
Im just wondering, why the fermi level rise up with raisng up the temperature when donors are present in Extrinsic semiconductor?

thanx

What does the density of states (number of states per unit energy interval) look like in the Extrinsic semiconductor? Is there a higher density of states below the fermi level?
 


thanx for yor hekp
 

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