The infra red light emitting diode (IR LED) is a gallium arsenide PN junction diode which emits a beam of radiant flux when forward biased. The infra red LED is also known as IR transmitter. It is a special purpose LED that transmits infra red rays in the range of 760 nm wavelength.
Working of IR LED:
The electrons from the N region recombine with excess holes of P region in a suitably designed recombination region lying in between P and N type region, when the PN junction is in forward biased. In infra red region recombination process involves radiation of energy in the form of photons. The photons if liberated from the region may either be reabsorbed in the structure or may leave the surface of IR LED in the form of radiant energy.