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Optoelectronics

Optoelectronics is the study and application of electronic devices that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation. Electro-optics is often erroneously used as a synonym, but is in fact a wider branch of physics that deals with all interactions between light and electric fields, whether or not they form part of an electronic device. LED (Light emitting diode)

Colors and Materials Conventional LEDs are made from a variety of inorganic semiconductor materials, the following table shows the available colors with wavelength range, voltage drop and material:

Color

Wavelength (nm)

Voltage (V)

Semi-conductor Material

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

Infrared

Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP)

Gallium(III) phosphide (GaP)

Yellow

Green

570 < λ < 590

500 < λ < 570

2,10 < ΔV < 2,18

Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP) Gallium(III) phosphide (GaP)

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)

Ultraviolet λ < 400

White

diamond (C) Aluminium nitride (AlN) 3,1 < ΔV < 4,4 Aluminium gallium nitride (AlGaN) Aluminium gallium indium nitride (AlGaInN) — (down to 210 nm[17])

Broad spectrum ΔV = 3,5

Blue/UV diode with phosphor