Electronics Handbook/Components/Diodes/Light Emitting

A light emitting diode (LED) emits colored light when it conducts electricity.

Colored Light Vd
Infrared 1.6 V
Red 1.8 V to 2.1 V
Orange 2.2 V
Yellow 2.4 V
Green 2.6 V
Blue 3.0 V to 3.5 V
White 3.0 V to 3.5 V
Ultraviolet 3.5 V
Construction Symbol I - V Curve

Colors and Materials

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Color Wavelength [nm] Voltage [V] Semi-conductor Material
Infrared λ > 760 ΔV < 1.9 Gallium arsenide (GaAs)
Aluminium gallium arsenide (AlGaAs)
Red 610 < λ < 760 1.63 < ΔV < 2.03 Aluminium gallium arsenide (AlGaAs)
Gallium arsenide phosphide (GaAsP)
Aluminium gallium indium phosphide (AlGaInP)
Gallium(III) phosphide (GaP)
Orange 590 < λ < 610 2.03 < ΔV < 2.10 Gallium arsenide phosphide (GaAsP)
Aluminium gallium indium phosphide (AlGaInP)
Gallium(III) phosphide (GaP)
Yellow 570 < λ < 590 2.10 < ΔV < 2.18 Gallium arsenide phosphide (GaAsP)
Aluminium gallium indium phosphide (AlGaInP)
Gallium(III) phosphide (GaP)
Green 500 < λ < 570 2.18 < ΔV < 4.0 Indium gallium nitride (InGaN) / Gallium(III) nitride (GaN)
Gallium(III) phosphide (GaP)
Aluminium gallium indium phosphide (AlGaInP)
Aluminium gallium phosphide (AlGaP)
Blue 450 < λ < 500 2.48 < ΔV < 3.7 Zinc selenide (ZnSe)
Indium gallium nitride (InGaN)
Silicon carbide (SiC) as substrate
Silicon (Si) as substrate — (under development)
Violet 400 < λ < 450 2.76 < ΔV < 4.0 Indium gallium nitride (InGaN)
Purple multiple types 2.48 < ΔV < 3.7 Dual blue/red LEDs,
blue with red phosphor,
or white with purple plastic
Ultraviolet λ < 400 3.1 < ΔV < 4.4 diamond (C)
Aluminium nitride (AlN)
Aluminium gallium nitride (AlGaN)
Aluminium gallium indium nitride (AlGaInN) — (down to 210 nm[1])
White Broad spectrum ΔV = 3.5 Blue/UV diode with yellow phosphor  
  1. "LEDs move into the ultraviolet". physicsworld.com. May 17, 2006. http://physicsworld.com/cws/article/news/24926. Retrieved 2007-08-13.