https://doi.org/10.1351/goldbook.LT07414
Semiconductor (often a combination of gallium, arsenic and phosphorous or gallium and nitrogen) containing an n region (where electrons are more numerous than positive charges) separated from a p region (where positive charges are more numerous than negative charges). Upon application of a voltage, charges move and emission of ultraviolet, visible or infrared radiation is produced each time a charge recombination takes place. Although a LED emits incoherent monochromatic light, normally a very narrow frequency range is obtained.
Notes:
- This effect is a form of electroluminescence.
- The colour depends on the semi-conducting material used, and can be ultraviolet, visible or infrared.
- Organic light-emitting devices (OLEDs) contain diodes made of small molecules or made of polymeric materials. The latter are sometimes called PLEDs.