The P type and N type materials are joined together to create a P-N junction. In case of no electricity flow the electrons occupy the holes on the P type material creating a depletion zone. The depletion zone acts as an insulating layer in the diode. In case the electric current is passed through the diode, the electrons in the N type material get attracted towards the P type material leading to removal of depletion zone. When the electrons meet the protons energy is released in the form of photons, which emit light. The energy of the band-gap is represented by the energy of the photons. The colour of the light depends on the wavelength and the type of material used in the semiconductor. The change in supply of current affects the flux of luminosity proportionately. LED in general are operated using direct currents to avoid the variation in the intensity of luminosity. The mechanism used is the “Injection Electroluminescence” where Luminescence signifies photon production; Electro suggests photon production using electric current and the Injection part deals with photon production using current carriers.
In general, the conducting material used in LED are Aluminium-Gallium-Arsenide (AlGaAs), the colour of the light depends upon the type of material used as a semiconductor. Some of the other materials used in production of semiconductors a part of LED are
Fig.1 –List of Semiconductor materials (LED, 2010) Organic Light Emitting diodes are also used where a thin film of organic material is coated over the semiconductors.
LED is made of semiconductor materials which are responsible for the production of light of various colours. In case of a static diode, when no electric current is passed the P type and N type materials attract respective protons and electrons at the respective ends. A depletion zone is created