Net current in a semiconductor

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Discussion Overview

The discussion revolves around the behavior of net current in semiconductors, particularly in the context of forward biasing a pn junction diode. Participants explore the implications of the built-in potential barrier and the conditions under which current flows when a voltage is applied.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant states that the built-in potential barrier Vb prevents any net current in a semiconductor until a battery is connected in forward bias with voltage V, even if V is less than Vb.
  • Another participant expresses uncertainty but suggests that if the textbook claims V cannot exceed Vb, it is likely true.
  • A participant speculates that exceeding Vb could eliminate the barrier, leading to excessive current that might damage the device, questioning if this could be the reason behind the textbook's statement.
  • There is a mention of the distinction between forward and reverse bias in diodes, indicating a need for clarity on these concepts.
  • One participant asks if others are familiar with the Diode Equation and its relationship between current and voltage for a pn junction diode, suggesting further exploration of this topic.

Areas of Agreement / Disagreement

Participants express differing levels of understanding and certainty regarding the implications of the built-in potential barrier and the conditions for current flow in semiconductors. No consensus is reached on the reasons behind the textbook's claim that V cannot exceed Vb.

Contextual Notes

Some participants note the lack of reasoning provided in the textbook for the claim about Vb, indicating that assumptions and definitions may be missing or unclear.

sahil_time
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We know that the built in potential barrier Vb does not allow any net current in a semiconductor. Now when we connect a battery in forward biased with the voltage V the current begins to flow even if V<Vb. Agreed. But my text says that V cannot exceed Vb is this true? for reference
http://books.google.co.in/books?id=...&resnum=6&ved=0CD0Q6AEwBQ#v=onepage&q&f=false
 
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I don't know much about this subject, but if that's what your textbook says then I'd say it is probably true.
 


The text didn't provide a reason. But i was thinking that if V>Vb there will be no barrier hence the current will be too large and that might damage the device. Can this be the reason?
 
Last edited by a moderator:


sahil_time said:
The text dint provide a reason. But i was thinking that if V>Vb there will be no barrier hence the current will be too large and that might damage the device. Can this be the reason?

No idea. Anyone else know?
 


sounds like its talking about diodes and pn junctions.

you do understand that there is forward and reverse bias?
 


yeah.yeah. so what do you propose?
 
Last edited by a moderator:


sahil_time said:
We know that the built in potential barrier Vb does not allow any net current in a semiconductor. Now when we connect a battery in forward biased with the voltage V the current begins to flow even if V<Vb. Agreed. But my text says that V cannot exceed Vb is this true? for reference
http://books.google.co.in/books?id=...&resnum=6&ved=0CD0Q6AEwBQ#v=onepage&q&f=false

sahil_time said:
yeah.yeah. so what do you propose?

Are you familiar with the Diode Equation? What is the relationship between current and voltage for a pn junction diode?

If you're not familiar with the equation yet, check wikipedia.com
 

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