Bandgap Values for GaAs and Si

• Defennder
In summary, the speaker is conducting a lab report on optical absorption of semiconductors and needs to verify the bandgap values for both GaAs and Si. They have tried searching on Google but were unsuccessful, so they ask for help from others. The bandgap values for Si and GaAs can be found at the given links, with the note that Si does not have a direct band gap.
Defennder
Homework Helper
I'm doing a lab report on optical absorption of semiconductors. As such I would like to verify the values of the bandgap Eg which I have calculated through experiment. I tried searching Google but I got a lot of results to technical papers which didn't help at all. I would like to know if anyone here can tell me the bandgap value for both GaAs and Si. Thanks.

Defennnder said:
I'm doing a lab report on optical absorption of semiconductors. As such I would like to verify the values of the bandgap Eg which I have calculated through experiment. I tried searching Google but I got a lot of results to technical papers which didn't help at all. I would like to know if anyone here can tell me the bandgap value for both GaAs and Si. Thanks.

Note that Si does not have a direct band gap, at least for the crystalline Si.

Zz.

Thanks Zz.

1) What is a bandgap value and why is it important in GaAs and Si materials?

A bandgap value is the energy difference between the top of the valence band and the bottom of the conduction band in a material. It is an important characteristic of semiconductors like GaAs and Si because it determines the energy needed for an electron to move from the valence band to the conduction band, thus allowing for electrical conductivity.

2) How does the bandgap value differ between GaAs and Si?

The bandgap value differs because of the different crystal structures and atomic compositions of GaAs and Si. GaAs has a direct bandgap, meaning that the top of the valence band and the bottom of the conduction band occur at the same momentum in the crystal. Si has an indirect bandgap, meaning that the top of the valence band and the bottom of the conduction band occur at different momenta. This results in a higher bandgap energy for Si compared to GaAs.

3) What is the typical bandgap value for GaAs and Si?

The typical bandgap value for GaAs is around 1.43 eV (electron volts), whereas the typical bandgap value for Si is around 1.12 eV. These values can vary slightly depending on the specific composition and crystalline structure of the material.

4) How does the bandgap value affect the electronic properties of GaAs and Si?

The bandgap value directly affects the electronic properties of GaAs and Si. A larger bandgap value means that more energy is required for electrons to move from the valence band to the conduction band, making it more difficult for the material to conduct electricity. This is why Si is often used in electronic devices as it has a smaller bandgap value and can easily conduct electricity.

5) Can the bandgap value of GaAs and Si be altered?

Yes, the bandgap value of GaAs and Si can be altered by introducing impurities or doping into the materials. This process, known as doping, can change the energy levels of the materials and thus alter their bandgap values. This is often done in the manufacturing of electronic devices to optimize their performance.

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