Electron & hole concentrations after doping silicon.

In summary, the Silicon wafer is doped with 2*10^16 cm^-3 Boron and 10^16 cm^-3 Phosphorous atoms, making it p-type with a hole concentration of 1*10^16 cm^-3 and an electron concentration of 2.25*10^4 cm^-3. The Fermi-level and resistivity at room temperature can be calculated using these values.
  • #1
Alex-012
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1. A Silicon wafer is doped with 2*10^16 cm^-3 Boron and 10^16 cm^-3 Phosphorous atoms. Calculate the electron and hole concentrations, the Fermi-level and the resistivity at room temperature

I have no idea how to work out the first part of this question as my lecture notes are lacking in material which wasn't discussed in the lecture and because I am at home for christmas I have no access to my recommended textbooks. If anyone could help me out I would be extremely grateful!
 
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  • #2
Ok, I think I was overthinking this. It seems easier than I originally thought.
I think the hole concentration is calculated using

Na - Nd = (2-1)x1016

since there are more acceptors than donors so therefore the silicon is p-type with a hole concentration of

[tex]1*10^{16} cm^{-3}[/tex]

Electron concentration is then calculated using:
[tex]np = n_{i}^2[/tex]

which gives

[tex]n = (1.5\times10^{10})^2/10^{16} = 2.25\times 10^{4} cm^{-3}[/tex]

Or am I way off the mark?
 

Related to Electron & hole concentrations after doping silicon.

1. What is doping in silicon?

Doping in silicon is the process of intentionally adding impurities to the silicon crystal structure in order to change its electrical properties.

2. How does doping affect electron and hole concentrations in silicon?

Doping introduces free charge carriers, either electrons or holes, into the silicon crystal. This changes the balance between the number of electrons and holes, resulting in an increase in either electron or hole concentration depending on the type of doping.

3. What are electron and hole concentrations?

Electron and hole concentrations refer to the number of free electrons and holes, respectively, in a semiconductor material such as silicon. These free charge carriers play a crucial role in the material's electrical conductivity.

4. How does the type of doping affect the electron and hole concentrations in silicon?

The type of doping, whether it is n-type or p-type, determines the majority carrier (either electrons or holes) and therefore affects the concentration of that carrier. For example, n-type doping increases the concentration of electrons, while p-type doping increases the concentration of holes.

5. What factors can influence the electron and hole concentrations after doping silicon?

The electron and hole concentrations after doping silicon can be influenced by various factors such as the type and amount of dopant used, temperature, and the presence of other impurities in the silicon crystal.

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