Draw and describe construction of LED .
Construction of LED
Fig above shows the construction of LED.
Here an N-type layer is grown on a substrate by a diffusion process.
Then a thin P-type layer is grown on the N-type layer.
The metal connections to both the layers make anode and cathode terminals as indicated.
The active region exists between the P and N regions.
The light energy is released at the junction when the electron hole pair recombination takes place.
After passing through the P-region the light is emitted from the window provided at top.