One of most important and basic Electrical Engineering Question is, Why LED is Not Made of made of silicon or germanium and is made of Gallium arsenide (GaAs), Gallium arsenide phosphide (GaAsP), or Gallium phosphide. In this article Electrical Engineering XYZ answers this question. Also download our Handbook on Top 50 Basic Electrical Engineering Questions here.
LEDs are built as p-n junction devices from materials like gallium arsenide (GaAs), gallium arsenide phosphide (GaAsP), or gallium phosphide (GaP). Silicon and germanium are unsuitable for this purpose as their junctions generate heat without significant production of infrared (IR) or visible light. In the LED, the junction is forward-biased, causing electrons to traverse from the n-type to the p-type material. This electron-hole recombination process, known as electroluminescence, results in the emission of photons in the infrared or visible spectrum. Consequently, the exposed semiconductor surface emits light.