A light-emitting diode (LED) is a semiconductor device that emits light when an electric current flows through it. Electroluminescence is the process where this happens: voltage applied to the semiconductor makes electrons flow across a junction, releasing energy as light.
- Semiconductors, typically made from gallium nitride, are solid-state materials with unique properties that allow them to emit light at specific wavelengths, determining the perceived colour.
- LEDs typically emit one colour with a narrow range of wavelengths.
- Multicoloured LEDs combine three diodes emitting the RGB primary colours – red, green, and blue light.
- By adjusting the relative brightness of the primary colours, a vast array of colours can be created.
- Combining the three primary colours in equal proportions produces white light.