Why Does N-Type Doping Result in Higher Hole than Electron Concentration?

In summary, we are given a semiconductor material with a bandgap energy of .1 eV and a density of states for the conduction and valence bands both equal to 10^18cm^-3. When doped with shallow donors (n-type) Nd=10^17cm^-3, the electron and hole concentrations are found using the equations ni=sqrt(Nc*Nv)*exp(-Eg/2kT), n+Na=p+Nd, and p=ni^2/n. When solving for the concentrations, it is important to note that the n concentration should be greater than the p concentration, as the material is doped n-type. However, if the math is done incorrectly, the opposite result may
  • #1
heehar
3
0

Homework Statement


Suppose an unknown semiconductor material has bandgap energy of .1 eV. Density of states for conduction and valence bands are both = 10^18cm^-3.
If the material is doped with shallow donors (n-type) Nd=10^17cm^-3, what is electron and hole concentrations?


Homework Equations


ni=sqrt(Nc*Nv)*exp(-Eg/2kT)
n+Na=p+Nd
p=ni^2/n

The Attempt at a Solution


so I set Na = 0. and solve the quadratic equation but I end up with a hole concentration greater than an electron concentration...why is that the case? isn't the fact that its doped n-type mean the n concentration is supposed to be greater?
 
Physics news on Phys.org
  • #2
You did the math wrong. With those conditions, I get n>p, with n~2*p. Did you mix up Na and Nd?
 
  • #3
you are right haha thanks
 

Related to Why Does N-Type Doping Result in Higher Hole than Electron Concentration?

What is doped semiconductor material?

Doped semiconductor material is a type of semiconductor material that has been intentionally altered or "doped" with impurities. These impurities are added in controlled amounts to modify the electrical and physical properties of the material.

What are the types of doping in semiconductor materials?

The two main types of doping in semiconductor materials are n-type doping and p-type doping. N-type doping involves adding impurities with extra electrons, while p-type doping involves adding impurities with fewer electrons than the host material.

What is the purpose of doping semiconductor materials?

Doping semiconductor materials is done to change their electrical properties in order to make them more useful for electronic devices. For example, n-type doping can make a material more conductive, while p-type doping can create areas of higher resistance.

What are the most commonly used dopants in semiconductor materials?

The most commonly used dopants in semiconductor materials are boron, phosphorus, arsenic, and antimony. These elements are used because they have the right electronic properties to change the behavior of the host material in a desired way.

How does doping affect the band structure of a semiconductor material?

Doping can affect the band structure of a semiconductor material by creating additional energy levels within the bandgap. This can result in a shift in the Fermi level and the creation of either n-type or p-type regions, depending on the type of doping used.

Similar threads

Semiconductor Physics : Charge carrier concentration change on doping
    • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
Why Does the Depletion Layer Affect Acceptor Atom Concentration in PN Junctions?
    • Engineering and Comp Sci Homework Help
Replies
3
Views
1K
Diffusion current and carrier concentration equilibrium (unbiased)
    • Electrical Engineering
Replies
1
Views
924
Concentration of minority carriers in a pn junction
    • Engineering and Comp Sci Homework Help
Replies
2
Views
10K
What exactly is a concentration of acceptor in p-type semiconductor
    • Engineering and Comp Sci Homework Help
Replies
4
Views
1K
Electron and hole concentration
    • Introductory Physics Homework Help
Replies
1
Views
931
Silicon NPN Transistor: Calculating Fermi-Level & Equilibrium Concentrations
    • Engineering and Comp Sci Homework Help
Replies
1
Views
1K
I Hall effect in P-type semiconductors: electron-centric heuristic?
    • Atomic and Condensed Matter
Replies
0
Views
198
Calc Electron/Hole Concentrations & Ef-Efi for Si Doping in GaAs
    • Advanced Physics Homework Help
Replies
7
Views
1K
Semiconductor Doping: Impurity Effects on Energy States
    • Introductory Physics Homework Help
Replies
9
Views
2K

Hot Threads

Recent Insights

Back
Top