Hello friends, in this article I am going to tell you about the structure of LED, What is LED, working method of LED uses of LED. so let’s start
What is LED (Light Emitting Diode)– It is a special type of semiconductor diode, which is designed to emit light. It works in forwarding bias.
LED’s Structure
- Gallium Arsenide (GaAs), Gallium Arsenide Phosphide (GaAsP), or Gallium Phosphide (GaP) are semiconductors used for LED manufacturing.
- An N-type epitaxial layer is grown on a substrate, now a P-type region is created on an N-type epitaxial layer by a diffusion process.
- Thus the recombination of the e-hole pair occurs in the P-type region. Now a thin layer of metal is applied on the surface of the P-type region which provides an anode connection.
- A gold film is applied to the bottom of the substrate, which provides the cathode connection.
- Now this LED structure is sealed in the plastic enclosure. There is a transparent window at the top of this plastic enclosure. It has a plastic lens that focuses the light in one line.
- Now to reflect maximum light from the external surface, a selected portion of the thin metal surface is removed.
- Read more: what is LDR?
Working of LED
When the P-N junction of an LED is in forwarding bias, current flows into the forward bias because free e in forwarding bias moves from the SN-side to the P-side, where electrons are recombined with holes. Free es is in the conduction band and their energy is more than the holes found in the valence band.
When electrons recombine with holes, electrons move from the conduction band to the valence band, where the electrons and holes recombine. The energy comes out in the form of heat and light.
The energy gap between the conduction band and the valence band is called the forbidden energy gap (Eg). The color of the light emitted from the LED depends on the material used in the manufacture of the LED. Generally LED is found in red, yellow, and green colors.
Different types of materials are used in LED for the emission of different colors as follows-
Colour Semiconductor material
Green GaP on Gap
Yellow GaAsP on Gap
Red GaAsP on Gap
uses of LED
(a) In the form of indicator light
(b) In communication as an octave display unit.
(c) LED optical fiber that produces high-intensity light in communication.
- Read more: What is Auto Transformer?
Now you must have known that the What is LED, structure of LED, working method of LED, uses LED.
If you have any questions or suggestions in your mind, then you can tell me by commenting, I will answer your comment, you can also share this article with your friend.