Help: What is Band-Edge and Near-Band-Edge Emission?

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In summary, Band-edge and near-band-edge emission refer to the light emitted by a material when it absorbs energy. This can be measured using techniques such as photoluminescence spectroscopy or electroluminescence, and is affected by factors such as bandgap energy, temperature, and material defects. It has applications in optoelectronics, photovoltaics, and LEDs, and differs from other types of emission due to its origin in electron-hole recombination in the material's energy bands.
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maxxlr8
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I understand that in photoluminescence band edge emission in direct band gap semiconductors originates from the recombination of electron and hole in the edge of conduction and valence bands. However, recently I have stumbled upon near-band-edge emission, which seem to suggest the existence of other levels. My question is:
  1. Is the level in the forbidden band?
  2. How does this level exist?

Thank you
 
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Near band edge emission may arise essentially from excitonic or other shallow trap states
 

What is Band-Edge and Near-Band-Edge Emission?

Band-edge and near-band-edge emission refer to the light emitted by a material when it absorbs energy. This energy causes electrons to move from the valence band to the conduction band, creating an electron-hole pair. When the electron recombines with the hole, it emits light.

How is Band-Edge and Near-Band-Edge Emission measured?

Band-edge and near-band-edge emission can be measured using techniques such as photoluminescence spectroscopy or electroluminescence. These methods involve shining a light or applying an electrical current to the material and measuring the resulting emitted light.

What factors affect the intensity of Band-Edge and Near-Band-Edge Emission?

The intensity of band-edge and near-band-edge emission can be affected by various factors, including the material's bandgap energy, temperature, and defects or impurities in the material. Additionally, the excitation source and measurement techniques can also impact the emission intensity.

What are the applications of Band-Edge and Near-Band-Edge Emission?

Band-edge and near-band-edge emission have various applications in fields such as optoelectronics, photovoltaics, and light-emitting diodes (LEDs). This emission can also provide valuable information about the electronic properties and quality of the material being studied.

How does Band-Edge and Near-Band-Edge Emission differ from other types of emission?

Band-edge and near-band-edge emission differ from other types of emission, such as free electron or defect emission, in that they are a result of electron-hole recombination in the material's energy bands. This type of emission is also typically characterized by a sharp and well-defined peak in the emission spectrum.

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