LED-Technologie: Funktionsweise und Details

LED (Light Emitting Diode) technology has revolutionized the world of lighting over the past few decades. LEDs are now found everywhere, from small displays to street lights. Let's explore how this amazing technology works in detail.

1. Basic principle of light emission

LEDs are semiconductor devices that emit light when electricity flows through them. This phenomenon is called electroluminescence. The process is based on the properties of certain semiconductor materials and works as follows:

  • PN junction : An LED consists of what is known as a PN junction. This means that it contains two semiconductor layers: a p-layer (positively doped) and an n-layer (negatively doped).

  • Electrons and holes : In the p-layer there are a large number of “holes” that act as positive charge carriers, while the n-layer contains a majority of electrons.

  • Current flow and recombination : When an electrical voltage is applied, the electrons and holes migrate to the junction region (the interface between the p- and n-layers) and recombine with each other. During this recombination, they release energy in the form of photons, which appear as visible light.

2. Colouring through choice of material

The color of the light produced by an LED depends on the semiconductor materials used, as these affect the band gap (energy difference between the electron and hole bands) and thus the energy of the photons produced. Here are some common materials and the resulting light colors:

  • Gallium arsenide (GaAs) : Infrared
  • Gallium Phosphide (GaP) : Red or Green
  • Indium Gallium Nitride (InGaN) : Blue or Green
  • Aluminium nitride (AlN) : UV

By combining different materials, LEDs can be produced in many colors. White LEDs are often made using a blue LED in combination with a yellow phosphor coating.

3. Efficiency and energy saving

LEDs are extremely energy efficient. They generate very little heat and have a high light output, making them superior to incandescent or fluorescent lamps. Here are some advantages of LED technology:

  • Long lifespan : LEDs can last up to 50,000 hours or more.
  • Low heat generation : The heat generation is low due to its efficiency.
  • Robustness : LEDs are shockproof and resistant to vibrations.

4. Application and progress

The possible applications are diverse. LEDs are used in the automotive industry, in street lighting, in displays, as indicators and in general room lighting. Advances in LED technology now enable higher brightness, efficiency and a wider range of colors.

Conclusion

LED technology is based on the principles of semiconductor physics and offers significant advantages in terms of energy efficiency and longevity. It is an essential component of modern lighting solutions today and will continue to play a crucial role in the future.

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