Indirect band gap semiconductor doubt

In summary, indirect band gap semiconductors like silicon and germanium are not ideal for use as light sources due to their higher rates of non-radiative recombinations, leading to decreased efficiency of optical sources. While some radiative photons are produced, the majority of recombinations result in phonons and heating of the semiconductor. Auger recombination may be responsible for this phenomenon.
  • #1
munna007
34
0
indirect band gap semiconductor doubt

its said that indirect band gap semiconductors like silicon and germanium are not used as a light sources because they have more non-radiative recombinations rather than radiative ,which inturn decreases efficiency of optical source.


but i want to understand how indirect band gap materials produce non-radiative photons.

i have studied many books like keiser , senior on optical fibre .those all are not explanatory on this ...also googled for this ,but not helped from there...


hoping for help here...thanks...love to all...
 

Attachments

  • indirect band gap.JPG
    indirect band gap.JPG
    26.4 KB · Views: 512
Engineering news on Phys.org
  • #2


The answer is that they do not produce non-radiative photons. There are a few radiative photons produced, but the majority of recombinations will result in phonons (lattice vibrations) and heating of the semiconductor. My semiconductor physics is a little rusty, but I think that Auger recombination is the phrase you're looking for.

The book I used for my condensed matter physics (which covered this) was Kittel's Introduction to Solid State Physics.
 

1. What is an indirect band gap semiconductor?

An indirect band gap semiconductor is a type of material that has a band gap between its valence and conduction bands. This means that the electrons in the conduction band cannot directly recombine with the holes in the valence band, and instead must undergo a change in momentum to do so.

2. How does an indirect band gap semiconductor differ from a direct band gap semiconductor?

An indirect band gap semiconductor differs from a direct band gap semiconductor in that the energy of an electron in the conduction band is not equal to the energy of a hole in the valence band. In a direct band gap semiconductor, the energy levels of the two are equal, allowing for easier recombination of electrons and holes.

3. What are some examples of indirect band gap semiconductors?

Some examples of indirect band gap semiconductors include silicon, germanium, and gallium arsenide. These materials are commonly used in electronic devices such as transistors and solar cells.

4. How does the band gap affect the properties of an indirect band gap semiconductor?

The band gap of an indirect band gap semiconductor affects its optical and electrical properties. Since the energy levels of electrons and holes are not equal, the material is less efficient at converting electrical energy into light and vice versa. This can also impact the material's ability to conduct electricity.

5. Can indirect band gap semiconductors be used in optoelectronic devices?

Yes, indirect band gap semiconductors can be used in optoelectronic devices such as LEDs and solar cells. While they may not be as efficient as direct band gap semiconductors, they are still important materials in the development of new technologies.

Similar threads

Why is the band gap in alloys such as GaAs less?
    • Electrical Engineering
Replies
1
Views
2K
Fundamentals of the PN Junction
    • Electrical Engineering
Replies
12
Views
1K
Photoluminescence at a heterojunction
    • Atomic and Condensed Matter
Replies
1
Views
1K
Why is P-N junction so important in semiconductor diodes?
    • Electrical Engineering
Replies
2
Views
4K
Band Gap of Semiconductor Materials
    • Atomic and Condensed Matter
Replies
6
Views
2K
B Radiation detector types/physics
    • High Energy, Nuclear, Particle Physics
Replies
24
Views
2K
Semiconductors - Flat band Diagram vs Equilibrium Diagram
    • Engineering and Comp Sci Homework Help
Replies
3
Views
3K
Why does the LED structure favorizes p-type semiconductor?
    • Atomic and Condensed Matter
Replies
1
Views
2K
What Triggers Electron-Hole Recombination in Semiconductors?
    • Atomic and Condensed Matter
Replies
1
Views
4K
I How to get plot (optical gain of GaAs)?
    • Atomic and Condensed Matter
Replies
2
Views
3K

Hot Threads

Recent Insights

Back
Top