# Factors that influence the spectral linewidth of an LED

• ma_donna_14
In summary, the factors that influence the spectral linewidth of the emission spectrum in an LED include the types of elements used in doping the semiconductor, the temperature of the LED, and the optical cavity design. It is important to consider these factors in order to optimize the performance and efficiency of the LED.
ma_donna_14
So I'm doing up a physics report but i got stuck on this question :(

Q: Explain the factors that influence the spectral linewidth of the emission spectrum.

i'm guessing that it has something to do with the types of elements used in doping the semiconductor? but i don't know how the theory part goes exactly.

ma_donna_14 said:
So I'm doing up a physics report but i got stuck on this question :(

Q: Explain the factors that influence the spectral linewidth of the emission spectrum.

i'm guessing that it has something to do with the types of elements used in doping the semiconductor? but i don't know how the theory part goes exactly.

Welcome to the PF.

berkeman said:
Welcome to the PF.

i've been googling extensively but i can't seem to find anything helpful... been flipping through notes but it doesn't mention spectral linewidth at all :-( sigh.

ma_donna_14 said:
i've been googling extensively but i can't seem to find anything helpful
Really? When I Google spectral linewidth of an LED (directly from your thread title), I get lots of great hits. The first hit on the list would seem to be a good answer...

## 1. What is the spectral linewidth of an LED?

The spectral linewidth of an LED refers to the width of the spectrum of light emitted by the LED. It is typically measured in terms of the full width at half maximum (FWHM), which is the width of the spectrum at half of the maximum intensity.

## 2. What factors influence the spectral linewidth of an LED?

There are several factors that can influence the spectral linewidth of an LED, including the size and shape of the LED, the materials used in the LED's construction, and the temperature of the LED. Additionally, the current and voltage applied to the LED can also affect its spectral linewidth.

## 3. How does the size and shape of an LED affect its spectral linewidth?

The size and shape of an LED can affect its spectral linewidth because they determine the size and distribution of the active region where light is emitted. LEDs with smaller and more uniform active regions tend to have narrower spectral linewidths, while larger and more irregularly shaped active regions can lead to broader linewidths.

## 4. Can the materials used in an LED impact its spectral linewidth?

Yes, the materials used in an LED can have a significant impact on its spectral linewidth. Different materials have different energy band structures, which can affect the wavelengths of light that are emitted and thus the spectral linewidth. Additionally, imperfections or defects in the materials can also contribute to broadening the spectral linewidth.

## 5. How does temperature affect the spectral linewidth of an LED?

Temperature can have a significant impact on the spectral linewidth of an LED. As the temperature of an LED increases, the atoms in the material start to vibrate more, which can cause variations in the energy levels and lead to a broadening of the spectral linewidth. In fact, temperature changes can have a larger impact on the spectral linewidth than any other factor.

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