Semiconductors, number density of charge carriers.

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SUMMARY

The discussion centers on calculating the number density of charge carriers in undoped silicon, specifically addressing a discrepancy between a student's calculated value of 6.13 x 1011 m-3 and the expected answer of 1.6 x 1012 m-3. Key factors influencing this calculation include the consideration of both electrons and holes as charge carriers, as well as the temperature used in the calculations, with a noted difference between 298K and the more commonly used 300K. The importance of including both types of charge carriers is emphasized as critical for accurate results.

PREREQUISITES
  • Understanding of semiconductor physics
  • Familiarity with charge carrier density calculations
  • Knowledge of temperature effects on semiconductor properties
  • Basic proficiency in algebra for solving equations
NEXT STEPS
  • Study the role of temperature in semiconductor behavior, focusing on 300K vs. 298K
  • Learn about the calculation of charge carrier densities in semiconductors
  • Explore the concept of holes as charge carriers in semiconductors
  • Review semiconductor doping effects on electron and hole concentrations
USEFUL FOR

Students studying semiconductor physics, educators teaching material on charge carriers, and professionals involved in semiconductor research and development.

elevenb
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Homework Statement



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It's the third part which I'm stuck on.

Homework Equations



gif.latex?\frac{N_{1}}{N_{0}}=e^{-\frac{E_{1}-E_{0}}{KT}}.gif

The Attempt at a Solution



I've substituted in all the numbers and, multiplied by the density but I am still not getting the correct answer; where a I going wrong?

I got

6.13*(10^11) m^-3

The answer given is

1.6*(10^12) m^-3
 
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"Third part" means the undoped silicon?
mc94 said:
I've substituted in all the numbers and, multiplied by the density but I am still not getting the correct answer; where a I going wrong?
There is no way to tell if you just show your answer instead of the actual work.
What did you use as room temperature?
 
mfb said:
"Third part" means the undoped silicon?
There is no way to tell if you just show your answer instead of the actual work.
What did you use as room temperature?

I took 298K as room temperature; and yes sorry I meant the part with the undoped silicon.
 
That is the number of electrons. You also have holes as charge carriers.

I get the given answer as rounded result with 300K instead of 298K.
 
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mfb said:
That is the number of electrons. You also have holes as charge carriers.

I get the given answer as rounded result with 300K instead of 298K.

Ahh the holes! I completely forgot, kicking myself now! Thank you!
 

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