Structure

Simple standard LEDs usually consist of an LED chip, a reflector with contact to the cathode (-), a gold wire as contact to the anode (+) and a plastic lens.

However, the structure shown above is just an example. In addition to the structure shown, there are also LEDs in high-power or SMD versions, for example.

The LED chip consists in principle of two layers. One layer has surplus electrons (n-type doping). The second, p-doped layer on the other hand has an electron deficiency; a majority of electron holes exists. This different charge distribution is achieved through the purposeful contamination (doping) of the pure semiconducting material, where other atoms such as boron or silicon are added to the semiconducting material. The illustration below shows this simplified structure of an LED chip. The emitted light is only directed by a reflector or a lens.