How is a light emitting diode fabricated ? Briefly state is working. Write any two important advantages of LEDs over the conventional incandescent low power lamps.

Explanation

In an LED the upper layer of p-type semiconductor is deposited by diffusion on n-type layer of semiconductor. The metallised contacts are provided for applying the forward bias voltage to the p-n junction diode from the battery through a resistance which controls the brightness of light emitted.