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Arthur202
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Can anybody explain my what is the origin of this forbidden gap?
I mean how it was created and what is the physics behind this issue?
I mean how it was created and what is the physics behind this issue?
Dr. Courtney said:
Arthur202 said:There isn't a real explanation there for the phenomenon as I have asked. i didn't ask what is it.
The band gap in semiconductors is the energy difference between the valence band (where electrons are bound to atoms) and the conduction band (where electrons are free to move and conduct electricity). It represents the minimum energy required for an electron to move from the valence band to the conduction band.
The size of the band gap directly affects the electrical conductivity of a semiconductor. A larger band gap means that electrons require more energy to move from the valence band to the conduction band, resulting in lower conductivity. On the other hand, a smaller band gap leads to higher conductivity as electrons can more easily move to the conduction band.
Yes, the band gap of a semiconductor can be changed by altering its chemical composition or through the process of doping, which involves introducing impurities into the crystal structure. For example, adding impurities with more valence electrons can decrease the band gap, while impurities with fewer valence electrons can increase the band gap.
The band gap also affects the optical properties of semiconductors. Materials with smaller band gaps tend to absorb shorter wavelengths of light, while materials with larger band gaps absorb longer wavelengths. This is why semiconductors with different band gaps are used in various electronic and optoelectronic devices such as solar cells and LEDs.
The band gap of semiconductors decreases as the temperature increases. This is because at higher temperatures, more electrons are excited and jump from the valence band to the conduction band, reducing the energy required for this transition. This phenomenon is known as band gap narrowing and can significantly affect the performance of semiconductor devices.