LED (Light Emitting Diode) is a semiconductor device that gives off light when applying current. Semiconductors are primarily classified as monotone semiconductors, compound semiconductors, and organic semiconductors, of which LED is a type of compound ones. A compound semiconductor is one made up of two or more elements, unlike a monotone semiconductor made up of silicon and germanium. LED is mainly made of gallium arsenide (GaAs), gallium phosphorus (GaP), gallium arsenide (GaAsP), and gallium nitrogen (GaN), and the color of LED light varies depending on what compound are used.
In short, LED is optical semiconductor that converts electrical energy into light energy. Basically, LED has a cross-component structure of p-type semiconductor with positive(+) electrical properties and n-type semiconductor with negative(-) electrical properties. N-type with a large number of electrons and p-type with positive characteristics from a lot of holes, as opposite concept, are attached in a thin layer and when applied in forward direction, the current flows to the voltage of several colts and emits light. In other words, n-type electron moves and combines with p-type hole and it emits energy, which is mainly emitted in the form of heat or light and LED is the immediate production of the form of light.