Behaviour of intrinsic semiconductor to an electric field

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Discussion Overview

The discussion centers on the behavior of intrinsic semiconductors in the presence of an electric field, particularly in the context of a p-i junction under forward bias. Participants explore the formation of the depletion region in intrinsic materials, the presence of free carriers, and the implications of these factors on current flow.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether current will flow in a p-i junction under forward bias and seeks clarification on the formation of the depletion region in the intrinsic region, which is suggested to lack free carriers.
  • Another participant argues that intrinsic silicon does have free carriers due to thermally generated electron-hole pairs, except in the depletion zone, challenging the assumption that there are no free carriers.
  • There is a query regarding the nature of ions left behind in the depletion region of intrinsic silicon, specifically whether they are negative or positive ions.
  • A later reply reiterates the question about the formation of a depletion region in intrinsic silicon and clarifies that depletion can occur when an intrinsic region adjoins a doped region, but not when it is energized without any junctions.

Areas of Agreement / Disagreement

Participants express differing views on the presence of free carriers in intrinsic silicon and the conditions under which a depletion region can form. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are assumptions regarding the behavior of intrinsic silicon and the conditions necessary for depletion region formation that are not fully explored or defined, leading to uncertainty in the discussion.

arunkumarcea
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If I have a semiconductor junction of p-i and an electric field applied to it in forward bias, will the current flow?. How is the depletion region formed in intrinsic region since there are no free carriers there.What will be the electric field distribution through the intrinsic region?
 
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What makes you believe there are no free carriers in intrinsic Si? Intrinsic Si has not been doped with any acceptor or donor elements, ideally it is pure Si. Electron-hole pairs are being thermally generated constantly just like with n and p type Si. The i layer has free carriers, except of course in a depletion zone. Did this help?

Claude
 
How can a depletion region be formed in intrinsic Si?Will they leave behind negative ions or positive ions?
 
arunkumarcea said:
How can a depletion region be formed in intrinsic Si?Will they leave behind negative ions or positive ions?

When an intrinsic region adjoins a doped region, there can be depletion. If a slab of intrinsic is energized w/o any p-n junctions then there is no depletion.

Claude
 

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