What is a LED – Light Emitting Diode?
-Anatomy of a Blinkee.com Product
Most of our products on Blinkee.com use LEDs of one color or another.
Hiding in Plain Sight
So what Exactly is a LED?
A LED is a light emmiting diode. Here is a simple introduction to how LEDs work:
A LED is a device made from semiconductor material that emits light when electricity is passed through it. Light is generated when an electron and an electron hole combine in the semiconductor material.
LEDs are known as solid state devices since the light is generated in the semiconductor material which is a solid.
Other lighting technologies such as heated filaments or fluorescent lamps are not considered solid state devices.
The electrons and electron holes are contained within energy bands inside the semiconductor material of the LED. The bandgap is the separation of the energy bands. The energy of the light particles known as photons is determined by this bandgap.
The wavelength, and consequently, the color of the light emitted by the LED is determined by the photon energy. Altering the material of the light-emitting or active region of the LED can tune the wavelength or color of the Light emitted.
Elements from group III and group V of the periodic table (known as III-V) materials) are the materials used for the semiconductor materials in LEDs. Some of these III-V materials are gallium arsenide (GaAs) and gallium phosphide (GaP).
Blue and white LEDs did not even exist until the mid 1990’s. Before that LED’s came in only red, green, yellow and orange. Gallium nitride (GaN) material added to LED production completed the range of colors possible.
Materials Used in LED Production
Indium gallium nitride (InGaN): blue, green and ultraviolet high-brightness LEDs
Aluminum gallium indium phosphide (AlGaInP): yellow, orange and red high-brightness LEDs
Aluminum gallium arsenide (AlGaAs): red and infrared LEDs
Gallium phosphide (GaP): yellow and green LEDs