Resistivity and Voltage in Intrinsic and Extrinsic Silicon Samples

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    Semiconductor
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Discussion Overview

The discussion revolves around the resistivity and voltage characteristics of intrinsic and extrinsic silicon samples, particularly in the context of a homework problem involving Ohm's law and semiconductor behavior. Participants explore the implications of these properties on current flow and voltage measurements.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a homework problem involving the resistivity of intrinsic and extrinsic silicon and seeks to determine the voltage across an intrinsic silicon bar using Ohm's law.
  • Another participant points out missing components in the homework template, specifically regarding the understanding of conduction and the steps taken to solve the problem.
  • A participant expresses confusion about applying Ohm's law to semiconductors, citing a claim that current flow in semiconductors is not linear and may not follow the V=IR relationship.
  • Another reply suggests that while deviations from Ohm's law can occur in certain conditions, such as in the "hot electron" regime, Ohm's law is generally applicable for common and practical systems.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of Ohm's law to semiconductor materials, with some asserting it is generally valid while others highlight potential non-linear behavior under specific conditions. The discussion remains unresolved regarding the extent to which Ohm's law can be applied in this context.

Contextual Notes

There are limitations regarding the assumptions made about semiconductor behavior, particularly in relation to the linearity of current flow and the conditions under which Ohm's law may deviate. The discussion does not clarify these assumptions or the specific conditions that may lead to non-linear behavior.

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Homework Statement



The resistivity at room temperature of intrinsic silicon is 2.3*103 Ωm and that of an "n" type extrinsic silicon sample is 8.33*10-2Ωm . A bar of this extrinsic silicon with 50*1000 mm has a steady current of 100μA across it. The voltage across the bar is found to be 50 mVolt.If the same bar is of intrinsic silicon,the voltage across the bar will be ?

Homework Equations


The Attempt at a Solution

 
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I think you forgot to fill out part 2 and 3 of the homework template. In other words: What do you know about conduction? What did you do so far? Where did you run into problems?
 
mfb said:
I think you forgot to fill out part 2 and 3 of the homework template. In other words: What do you know about conduction? What did you do so far? Where did you run into problems?

The thing is i solved the question by using ohm's law but when i asked someone they said current flow through semiconductor is not linear and it won't follow V=IR so that is why i was confused.
 
There is a point where deviations from Ohm's law appear due to collision processes caused by very high internal electric fields. This is called the "hot electron" regime. It takes some effort to get there, however, so you needn't worry about it for common and practical systems. Ohm's law works fine in general.
 

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