Question

Explain the working of LED.

Answer 1

Working of LED:

1. When the LED is forward biased, electrons from the semiconductor's conduction band recombine with holes from the valence band releasing sufficient energy to produce photons that emit monochromatic light.
2. Because of the thin layer, a reasonable number of these photons can leave the junction and emit coloured light.
3. The amount of light output is directly proportional to the forward current. Thus, the higher the forward current, the higher is the light output.
4. The given figure schematically shows the emission of light when the electron-hole pair combines.
   
   Working of LED