Semiconductor Photoluminescene

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In summary, the conversation discusses the understanding and attempted answers regarding the detection of light emission at a specific wavelength due to band-to-band recombination in a semiconductor. It also explores the implications of this phenomenon, such as the determination of the bandgap of the semiconductor and the capture of electrons by energy levels induced by impurities.
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Homework Statement
A semiconductor material is characterized by photoluminescence (PL)
measurement, light emission at the wavelength of 326.3 nm due to band-to-
band recombination is detected. In addition, radiation due to the transition
from the conduction band to an impurity level at the wavelength of 885.7 nm is
also observed. Calculate the bandgap (in eV) of the semiconductor, and
determine the energy (in eV) of the impurity level with respect to the valence
band. The wavelength of light for PL excitation is 280 nm.
Relevant Equations
Eg=1.24/wavelength
Just wanted to check my understanding as well as my attempted answers here:

Since light emission at the wavelength of 326.3 nm due to band-to-band recombination is detected, this means that the electron falls down to the valence band to recombine with a hole (to occupy an empty state close to Ev) and emit a photon with energy close to Eg, hence 1.24/0.3263 = 3.8eV is the bandgap of the semiconductor?

For part 2, since the electron is captured by an energy level induced by impurities such as the energy level from a donor (ED), energy = 1.24/0.8857 - 1.4eV?

Thanks.
 
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jisbon said:
Just wanted to check my understanding as well as my attempted answers here:

Since light emission at the wavelength of 326.3 nm due to band-to-band recombination is detected, this means that the electron falls down to the valence band to recombine with a hole (to occupy an empty state close to Ev) and emit a photon with energy close to Eg, hence 1.24/0.3263 = 3.8eV is the bandgap of the semiconductor?

For part 2, since the electron is captured by an energy level induced by impurities such as the energy level from a donor (ED), energy = 1.24/0.8857 - 1.4eV?

Thanks.
Correct.
 

1. What is semiconductor photoluminescence?

Semiconductor photoluminescence is a process in which a semiconductor material emits light when it is excited by a light source or electrical current. This phenomenon is commonly observed in materials such as silicon, gallium arsenide, and indium phosphide, which are widely used in electronic devices.

2. How does semiconductor photoluminescence occur?

When a semiconductor material is excited by a light source or electrical current, electrons in the material are promoted to higher energy levels. As these electrons return to their original energy levels, they release energy in the form of photons, resulting in the emission of light.

3. What are the applications of semiconductor photoluminescence?

Semiconductor photoluminescence has a wide range of applications, including in optoelectronic devices such as LEDs, solar cells, and lasers. It is also used in scientific research for studying the properties of semiconductors and in medical imaging for detecting diseases.

4. How is semiconductor photoluminescence different from fluorescence?

Semiconductor photoluminescence and fluorescence are both processes in which a material emits light. However, fluorescence occurs in organic molecules, while semiconductor photoluminescence occurs in inorganic materials such as semiconductors. Additionally, fluorescence is typically a slower process and involves the absorption of light at one wavelength and the emission of light at a longer wavelength, while semiconductor photoluminescence involves the absorption of light and the emission of light at the same wavelength.

5. What factors affect the photoluminescence efficiency of a semiconductor material?

The photoluminescence efficiency of a semiconductor material can be affected by various factors, including the material's purity, crystal structure, and temperature. The presence of impurities or defects in the material can reduce the efficiency of photoluminescence. Additionally, the crystal structure of the material can affect the energy levels of the electrons, which can impact the efficiency of photoluminescence. Finally, temperature can also play a role, as higher temperatures can cause thermal energy to be released instead of light, reducing the efficiency of photoluminescence.

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