How Do LEDs Work?

These days, LEDs are everywhere. With their impressive energy efficiency, extra long rated lives, and extraordinary versatility, they’re the lighting world’s new champion.

While it’s pretty easy to figure out what these lights can do, it’s harder to learn how they do it. If you’ve been wondering how exactly LEDs pull it off, just sit back and let this post “illuminate” you.

If you take a look at a single light emitting diode, you’ll notice that it resembles a tiny light bulb. BUT the similarities stop there. LEDs don’t have filaments like regular incandescent lights. Electrons moving across a semiconductor material cause them to create light. To understand this process, you first need to understand the LED’s components:

• A diode is the simplest kind of semiconductor, which is a material that can conduct electricity. For LED lights, the conductor material is most often aluminum-gallium-arsenide (AlGaAs).

• To make the semiconductor more conductive, you add atoms of another material, a process called doping. These atoms charge the conductor’s balance, either adding free electrons or providing holes for them to enter.

• A semiconductor that has extraneous electrons zipping around is called N-type material for its surplus of negatively charges particles. Electrons here proceed from negatively to positively charged materials.

• A semiconductor full of extra holes is called P-type material. It has, in essence, extra positively charged particles. Here, electrons can hop from one hole to the next, from a negatively charged area to a positive one.

• A diode needs both N-type and P-type material bonded together, with electrodes on either end. When you connect the N-type side to the negative end of a circuit, and the P-type side to the positive end, the electrons move towards the P-type area. The holes move in the opposite direction, away from the P-type, towards the N-type.

• Then, suddenly, there’s light!

How LEDs Create Light:

When the free electrons from the N-type area fall into holes from the P-type area, they must drop into lower orbitals around their atoms. Electrons in different orbitals have different amounts of energy, so the electron releases energy in the form of photons (light!).

This process can happen in any diode, but it’s only visible to the human eye when the diode is made of certain materials. A silicon diode, for example, has such small gaps for the electrons to jump that we can’t see their photons – the frequency is too low.

In order to produce visible light, the electron must drop a greater distance. The length of the drop determines the photon’s frequency, or in other words, the color of the light. Red LEDs are made from a different material than blue LEDs, and so on.

And that, folks, is how those LED light bulbs and light fixtures flood your rooms with beautiful, efficient light. For more information on LEDs, how they work, and what to expect out of them, check out this article on our website.